Regenerate all READMEs

exercises/accumulate/README.md

 provided by your standard library!
 Solve this one yourself using other basic tools instead.
 
-Lisp specific: it's perfectly fine to use `MAPCAR` or the equivalent,
-as this is idiomatic Lisp, not a library function.
-
 
 To run the tests:
 

exercises/acronym/README.md

 like Portable Network Graphics to its acronym (PNG).
 
 
-
 To run the tests:
 
 ```sh

exercises/all-your-base/README.md

 represented as a sequence of digits, convert it to base **b**.
 
 ## Note
+
 - Try to implement the conversion yourself.
   Do not use something else to perform the conversion for you.
 
 
 I think you got the idea!
 
-
 *Yes. Those three numbers above are exactly the same. Congratulations!*
 
 

exercises/allergies/README.md

 score is 257, your program should only report the eggs (1) allergy.
 
 
-
 To run the tests:
 
 ```sh

exercises/atbash-cipher/README.md

 
 An Atbash cipher for the Latin alphabet would be as follows:
 
-```plain
+```text
 Plain:  abcdefghijklmnopqrstuvwxyz
 Cipher: zyxwvutsrqponmlkjihgfedcba
 ```
 things based on word boundaries.
 
 ## Examples
+
 - Encoding `test` gives `gvhg`
 - Decoding `gvhg` gives `test`
 - Decoding `gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt` gives `thequickbrownfoxjumpsoverthelazydog`

exercises/beer-song/README.md

 
 Note that not all verses are identical.
 
-```plain
+```text
 99 bottles of beer on the wall, 99 bottles of beer.
 Take one down and pass it around, 98 bottles of beer on the wall.
 

exercises/binary/README.md

 program should handle invalid inputs.
 
 ## Note
+
 - Implement the conversion yourself.
   Do not use something else to perform the conversion for you.
 
 ## About Binary (Base-2)
+
 Decimal is a base-10 system.
 
 A number 23 in base 10 notation can be understood

exercises/book-store/README.md

 To try and encourage more sales of different books from a popular 5 book
 series, a bookshop has decided to offer discounts on multiple book purchases.
 
-One copy of any of the five books costs $8. 
+One copy of any of the five books costs $8.
 
 If, however, you buy two different books, you get a 5%
 discount on those two books.
 
-If you buy 3 different books, you get a 10% discount. 
+If you buy 3 different books, you get a 10% discount.
 
 If you buy 4 different books, you get a 20% discount.
 
-If you buy all 5, you get a 25% discount. 
+If you buy all 5, you get a 25% discount.
 
 Note: that if you buy four books, of which 3 are
 different titles, you get a 10% discount on the 3 that
-form part of a set, but the fourth book still costs $8. 
+form part of a set, but the fourth book still costs $8.
 
 Your mission is to write a piece of code to calculate the
 price of any conceivable shopping basket (containing only
 - 2 copies of the third book
 - 1 copy of the fourth book
 - 1 copy of the fifth book
- 
+
 One way of grouping these 8 books is:
 
 - 1 group of 5 --> 25% discount (1st,2nd,3rd,4th,5th)

exercises/bowling/README.md

 
 Score a bowling game.
 
-Bowling is game where players roll a heavy ball to knock down pins
+Bowling is a game where players roll a heavy ball to knock down pins
 arranged in a triangle. Write code to keep track of the score
 of a game of bowling.
 
 ## Scoring Bowling
 
-The game consists of 10 frames. A frame is composed of one or two ball throws with 10 pins standing at frame initialization. There are three cases for the tabulation of a frame.
+The game consists of 10 frames. A frame is composed of one or two ball
+throws with 10 pins standing at frame initialization. There are three
+cases for the tabulation of a frame.
 
-* An open frame is where a score of less than 10 is recorded for the frame. In this case the score for the frame is the number of pins knocked down.
+* An open frame is where a score of less than 10 is recorded for the
+  frame. In this case the score for the frame is the number of pins
+  knocked down.
 
-* A spare is where all ten pins are knocked down after the second throw. The total value of a spare is 10 plus the number of pins knocked down in their next throw.
+* A spare is where all ten pins are knocked down by the second
+  throw. The total value of a spare is 10 plus the number of pins
+  knocked down in their next throw.
 
-* A strike is where all ten pins are knocked down after the first throw. The total value of a strike is 10 plus the number of pins knocked down in their next two throws. If a strike is immediately followed by a second strike, then we can not total the value of first strike until they throw the ball one more time.
+* A strike is where all ten pins are knocked down by the first
+  throw. The total value of a strike is 10 plus the number of pins
+  knocked down in the next two throws. If a strike is immediately
+  followed by a second strike, then the value of the first strike
+  cannot be determined until the ball is thrown one more time.
 
 Here is a three frame example:
 
 
 This means the current running total is 48.
 
-The tenth frame in the game is a special case. If someone throws a strike or a spare then they get a fill ball. Fill balls exist to calculate the total of the 10th frame. Scoring a strike or spare on the fill ball does not give the player more fill balls. The total value of the 10th frame is the total number of pins knocked down.
+The tenth frame in the game is a special case. If someone throws a
+strike or a spare then they get a fill ball. Fill balls exist to
+calculate the total of the 10th frame. Scoring a strike or spare on
+the fill ball does not give the player more fill balls. The total
+value of the 10th frame is the total number of pins knocked down.
 
 For a tenth frame of X1/ (strike and a spare), the total value is 20.
 

exercises/change/README.md

 
 ## Source
 
-Software Craftsmanship - Kata-logue [http://craftsmanship.sv.cmu.edu/exercises/coin-change-kata](http://craftsmanship.sv.cmu.edu/exercises/coin-change-kata)
+Software Craftsmanship - Coin Change Kata [https://web.archive.org/web/20130115115225/http://craftsmanship.sv.cmu.edu:80/exercises/coin-change-kata](https://web.archive.org/web/20130115115225/http://craftsmanship.sv.cmu.edu:80/exercises/coin-change-kata)
 
 ## Submitting Incomplete Solutions
 It's possible to submit an incomplete solution so you can see how others have completed the exercise.

exercises/circular-buffer/README.md

 When the buffer is full an error will be raised, alerting the client
 that further writes are blocked until a slot becomes free.
 
-The client can opt to overwrite the oldest data with a forced write. In
-this case, two more elements — A & B — are added and they overwrite the
-3 & 4:
+When the buffer is full, the client can opt to overwrite the oldest
+data with a forced write. In this case, two more elements — A & B —
+are added and they overwrite the 3 & 4:
 
     [6][7][8][9][A][B][5]
 
-Finally, if two elements are now removed then what would be returned is
-not 3 & 4 but 5 & 6 because A & B overwrote the 3 & the 4 yielding the
-buffer with:
+3 & 4 have been replaced by A & B making 5 now the oldest data in the
+buffer. Finally, if two elements are removed then what would be
+returned is 5 & 6 yielding the buffer:
 
     [ ][7][8][9][A][B][ ]
 
+Because there is space available, if the client again uses overwrite
+to store C & D then the space where 5 & 6 were stored previously will
+be used not the location of 7 & 8. 7 is still the oldest element and
+the buffer is once again full.
+
+    [D][7][8][9][A][B][C]
+
 
 To run the tests:
 

exercises/collatz-conjecture/README.md

 Given a number n, return the number of steps required to reach 1.
 
 ## Examples
+
 Starting with n = 12, the steps would be as follows:
 
 0. 12
 Resulting in 9 steps. So for input n = 12, the return value would be 9.
 
 
-
 To run the tests:
 
 ```sh

exercises/complex-numbers/README.md

 
 A complex number is a number in the form `a + b * i` where `a` and `b` are real and `i` satisfies `i^2 = -1`.
 
+`a` is called the real part and `b` is called the imaginary part of `z`.
+The conjugate of the number `a + b * i` is the number `a - b * i`.
+The absolute value of a complex number `z = a + b * i` is a real number `|z| = sqrt(a^2 + b^2)`. The square of the absolute value `|z|^2` is the result of multiplication of `z` by its complex conjugate.
+
+The sum/difference of two complex numbers involves adding/subtracting their real and imaginary parts separately:
+`(a + i * b) + (c + i * d) = (a + c) + (b + d) * i`,
+`(a + i * b) - (c + i * d) = (a - c) + (b - d) * i`.
+
+Multiplication result is by definition
+`(a + i * b) * (c + i * d) = (a * c - b * d) + (b * c + a * d) * i`.
+
+The reciprocal of a non-zero complex number is
+`1 / (a + i * b) = a/(a^2 + b^2) - b/(a^2 + b^2) * i`.
+
+Dividing a complex number `a + i * b` by another `c + i * d` gives:
+`(a + i * b) / (c + i * d) = (a * c + b * d)/(c^2 + d^2) + (b * c - a * d)/(c^2 + d^2) * i`.
+
+Exponent of a complex number can be expressed as
+`exp(a + i * b) = exp(a) * exp(i * b)`,
+and the last term is given by Euler's formula `exp(i * b) = cos(b) + i * sin(b)`.
+
+
+Implement the following operations:
+ - addition, subtraction, multiplication and division of two complex numbers,
+ - conjugate, absolute value, exponent of a given complex number.
+
+
 Assume the programming language you are using does not have an implementation of complex numbers.
 
 

exercises/crypto-square/README.md

 Our normalized text is 54 characters long, dictating a rectangle with
 `c = 8` and `r = 7`:
 
-```plain
+```text
 ifmanwas
 meanttos
 tayonthe
 
 The message above is coded as:
 
-```plain
+```text
 imtgdvsfearwermayoogoanouuiontnnlvtwttddesaohghnsseoau
 ```
 
-Output the encoded text in chunks.  Phrases that fill perfect squares
-`(r X r)` should be output in `r`-length chunks separated by spaces.
-Imperfect squares will have `n` empty spaces.  Those spaces should be distributed evenly across the last `n` rows.
+Output the encoded text in chunks.  Phrases that fill perfect rectangles
+`(r X c)` should be output `c` chunks of `r` length, separated by spaces.
+Phrases that do not fill perfect rectangles will have `n` empty spaces.
+Those spaces should be distributed evenly, added to the end of the last
+`n` chunks.
 
-```plain
-imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau
+```text
+imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau 
 ```
 
 Notice that were we to stack these, we could visually decode the
 cyphertext back in to the original message:
 
-```plain
+```text
 imtgdvs
 fearwer
 mayoogo

exercises/diamond/README.md

 # Diamond
 
-The diamond kata takes as its input a letter, and outputs it in a diamond 
-shape. Given a letter, it prints a diamond starting with 'A', with the 
+The diamond kata takes as its input a letter, and outputs it in a diamond
+shape. Given a letter, it prints a diamond starting with 'A', with the
 supplied letter at the widest point.
 
 ## Requirements
 * The diamond has a square shape (width equals height).
 * The letters form a diamond shape.
 * The top half has the letters in ascending order.
-* The bottom half has the letters in descending order. 
+* The bottom half has the letters in descending order.
 * The four corners (containing the spaces) are triangles.
 
 ## Examples
 
 Diamond for letter 'A':
 
-```plain
+```text
 A
 ```
 
 Diamond for letter 'C':
 
-```plain
+```text
 ··A··
 ·B·B·
 C···C
 
 Diamond for letter 'E':
 
-```plain
+```text
 ····A····
 ···B·B···
 ··C···C··

exercises/etl/README.md

 We are going to do the `Transform` step of an Extract-Transform-Load.
 
 ### ETL
+
 Extract-Transform-Load (ETL) is a fancy way of saying, "We have some crufty, legacy data over in this system, and now we need it in this shiny new system over here, so
 we're going to migrate this."
 
 moaning about how stupid we could possibly be.)
 
 ### The goal
+
 We're going to extract some scrabble scores from a legacy system.
 
 The old system stored a list of letters per score:

exercises/flatten-array/README.md

 Take a nested list and return a single flattened list with all values except nil/null.
 
 The challenge is to write a function that accepts an arbitrarily-deep nested list-like structure and returns a flattened structure without any nil/null values.
- 
+
 For Example
 
 input: [1,[2,3,null,4],[null],5]
 output: [1,2,3,4,5]
 
 
-
 To run the tests:
 
 ```sh

exercises/food-chain/README.md

 
 This is one of many common variants.
 
-```plain
+```text
 I know an old lady who swallowed a fly.
 I don't know why she swallowed the fly. Perhaps she'll die.
 

exercises/grade-school/README.md

 Note that all our students only have one name.  (It's a small town, what
 do you want?)
 
-
 ## For bonus points
 
 Did you get the tests passing and the code clean? If you want to, these

exercises/house/README.md

 
 - [papyr.com](http://papyr.com/hypertextbooks/grammar/ph_noun.htm)
 
-
 The nursery rhyme reads as follows:
 
-```plain
+```text
 This is the house that Jack built.
 
 This is the malt

exercises/isogram/README.md

 
 Determine if a word or phrase is an isogram.
 
-An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter.
+An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter, however spaces and hyphens are allowed to appear multiple times.
 
 Examples of isograms:
 
 - lumberjacks
 - background
 - downstream
+- six-year-old
 
 The word *isograms*, however, is not an isogram, because the s repeats.
 

exercises/kindergarten-garden/README.md

 Given a diagram, determine which plants each child in the kindergarten class is
 responsible for.
 
-The kindergarten class is learning about growing plants. The teachers
+The kindergarten class is learning about growing plants. The teacher
 thought it would be a good idea to give them actual seeds, plant them in
 actual dirt, and grow actual plants.
 
 They've chosen to grow grass, clover, radishes, and violets.
 
-To this end, they've put little styrofoam cups along the window sills,
-and planted one type of plant in each cup, choosing randomly from the
-available types of seeds.
+To this end, the children have put little cups along the window sills, and 
+planted one type of plant in each cup, choosing randomly from the available 
+types of seeds.
 
-```plain
+```text
 [window][window][window]
-........................ # each dot represents a styrofoam cup
+........................ # each dot represents a cup
 ........................
 ```
 
 - Eve, Fred, Ginny, Harriet,
 - Ileana, Joseph, Kincaid, and Larry.
 
-Each child gets 4 cups, two on each row. The children are assigned to
-cups in alphabetical order.
+Each child gets 4 cups, two on each row. Their teacher assigns cups to 
+the children alphabetically by their names.
 
 The following diagram represents Alice's plants:
 
-```plain
+```text
 [window][window][window]
 VR......................
 RG......................
 ```
 
-So in the row nearest the window, she has a violet and a radish; in the
-row behind that, she has a radish and some grass.
+In the first row, nearest the windows, she has a violet and a radish.  In the
+second row she has a radish and some grass.
 
 Your program will be given the plants from left-to-right starting with
 the row nearest the windows. From this, it should be able to determine
-which plants belong to which students.
+which plants belong to each student.
 
 For example, if it's told that the garden looks like so:
 
-```plain
+```text
 [window][window][window]
 VRCGVVRVCGGCCGVRGCVCGCGV
 VRCCCGCRRGVCGCRVVCVGCGCV

exercises/linked-list/README.md

 
 Implement a doubly linked list.
 
-Like an array, a linked list is a simple linear data structure. Several 
-common data types can be implemented using linked lists, like queues, 
+Like an array, a linked list is a simple linear data structure. Several
+common data types can be implemented using linked lists, like queues,
 stacks, and associative arrays.
 
-A linked list is a collection of data elements called *nodes*. In a 
-*singly linked list* each node holds a value and a link to the next node. 
-In a *doubly linked list* each node also holds a link to the previous 
+A linked list is a collection of data elements called *nodes*. In a
+*singly linked list* each node holds a value and a link to the next node.
+In a *doubly linked list* each node also holds a link to the previous
 node.
 
-You will write an implementation of a doubly linked list. Implement a 
-Node to hold a value and pointers to the next and previous nodes. Then 
-implement a List which holds references to the first and last node and 
+You will write an implementation of a doubly linked list. Implement a
+Node to hold a value and pointers to the next and previous nodes. Then
+implement a List which holds references to the first and last node and
 offers an array-like interface for adding and removing items:
 
 * `push` (*insert value at back*);
 * `shift` (*remove value at front*).
 * `unshift` (*insert value at front*);
 
-To keep your implementation simple, the tests will not cover error 
-conditions. Specifically: `pop` or `shift` will never be called on an 
+To keep your implementation simple, the tests will not cover error
+conditions. Specifically: `pop` or `shift` will never be called on an
 empty list.
 
 If you want to know more about linked lists, check [Wikipedia](https://en.wikipedia.org/wiki/Linked_list).

exercises/list-ops/README.md

 
 ## Hints
 
+In Java it's considered best practice to use instance methods over class methods. However, there are conditions in which it is absolutely appropriate for a function to be `static`. Since classes in Java are closed for modification (i.e. you cannot add members to a class outside its definition like you can in other languages like Ruby or JavaScript), you cannot add new behavior to the class directly. What to do if you still want to define behavior for a given type? The idiomatic solution in this case is to write a utility method. 
+Collections of these kinds of methods are often referred to as "utility classes". Examples of such classes from within the JRE include [Arrays](https://docs.oracle.com/javase/9/docs/api/java/util/Arrays.html) and [Collections](https://docs.oracle.com/javase/9/docs/api/java/util/Collections.html).
+In this exercise we want a List to have `map()`, `reduce()`, `filter()`, etc. methods. It doesn't, so we're using static methods.
+
 The `foldLeft` and `foldRight` methods are "fold" functions, which is a concept well-known in the functional programming world, but less so in the object-oriented one. See the Wikipedia page on folding for [general background](https://en.wikipedia.org/wiki/Fold_(higher-order_function)) and [signature/implementation hints](https://en.wikipedia.org/wiki/Fold_(higher-order_function)#Linear_folds).
 
 

exercises/luhn/README.md

 
 ## Example 1: valid credit card number
 
-```
+```text
 4539 1488 0343 6467
 ```
 
 The first step of the Luhn algorithm is to double every second digit,
 starting from the right. We will be doubling
 
-```
+```text
 4_3_ 1_8_ 0_4_ 6_6_
 ```
 
 If doubling the number results in a number greater than 9 then subtract 9
 from the product. The results of our doubling:
 
-```
+```text
 8569 2478 0383 3437
 ```
 
 Then sum all of the digits:
 
-```
+```text
 8+5+6+9+2+4+7+8+0+3+8+3+3+4+3+7 = 80
 ```
 
 
 ## Example 2: invalid credit card number
 
-```
+```text
 8273 1232 7352 0569
 ```
 
 Double the second digits, starting from the right
 
-```
+```text
 7253 2262 5312 0539
 ```
 
 Sum the digits
 
-```
+```text
 7+2+5+3+2+2+6+2+5+3+1+2+0+5+3+9 = 57
 ```
 

exercises/matrix/README.md

 
 So given a string with embedded newlines like:
 
-> 9 8 7  
-> 5 3 2  
-> 6 6 7  
+```text
+9 8 7
+5 3 2
+6 6 7
+```
 
 representing this matrix:
 
-```plain
+```text
     0  1  2
   |---------
 0 | 9  8  7

exercises/meetup/README.md

 (Monday, Tuesday, ...) will have exactly one date that is named with '-teenth'
 in every month.
 
-Given examples of a meetup dates, each containing a month, day, year, and descriptor 
+Given examples of a meetup dates, each containing a month, day, year, and descriptor
 (first, second, teenth, etc), calculate the date of the actual meetup.
 For example, if given "First Monday of January 2017", the correct meetup date is 2017/1/2
- 
 
 
 To run the tests:

exercises/nucleotide-count/README.md

 # Nucleotide Count
 
-Given a DNA string, compute how many times each nucleotide occurs in the string.
+Given a single stranded DNA string, compute how many times each nucleotide occurs in the string.
 
-DNA is represented by an alphabet of the following symbols: 'A', 'C',
-'G', and 'T'.
-
-Each symbol represents a nucleotide, which is a fancy name for the
-particular molecules that happen to make up a large part of DNA.
-
-Shortest intro to biochemistry EVAR:
+The genetic language of every living thing on the planet is DNA. 
+DNA is a large molecule that is built from an extremely long sequence of individual elements called nucleotides. 
+4 types exist in DNA and these differ only slightly and can be represented as the following symbols: 'A' for adenine, 'C' for cytosine, 'G' for guanine, and 'T' thymine.
 
+Here is an analogy:
 - twigs are to birds nests as
-- nucleotides are to DNA and RNA as
-- amino acids are to proteins as
-- sugar is to starch as
-- oh crap lipids
-
-I'm not going to talk about lipids because they're crazy complex.
-
-So back to nucleotides.
-
-DNA contains four types of them: adenine (`A`), cytosine (`C`), guanine
-(`G`), and thymine (`T`).
-
-RNA contains a slightly different set of nucleotides, but we don't care
-about that for now.
+- nucleotides are to DNA as
+- legos are to lego houses as
+- words are to sentences as...
 
 
 To run the tests:

exercises/ocr-numbers/README.md

 
 The binary font uses pipes and underscores, four rows high and three columns wide.
 
-```
+```text
      _   #
     | |  # zero.
     |_|  #
 
 Is converted to "0"
 
-```
+```text
          #
       |  # one.
       |  #
 
 Update your program to recognize all numbers 0 through 9, both individually and as part of a larger string.
 
-```
+```text
  _ 
  _|
 |_ 
 
 Is converted to "2"
 
-```
+```text
       _  _     _  _  _  _  _  _  #
     | _| _||_||_ |_   ||_||_|| | # decimal numbers.
     ||_  _|  | _||_|  ||_| _||_| #
 
 Update your program to handle multiple numbers, one per line. When converting several lines, join the lines with commas.
 
-```
+```text
     _  _ 
   | _| _|
   ||_  _|

exercises/octal/README.md

 string, your program should produce a decimal output.
 
 ## Note
+
 - Implement the conversion yourself.
   Do not use something else to perform the conversion for you.
 - Treat invalid input as octal 0.
 
 ## About Octal (Base-8)
+
 Decimal is a base-10 system.
 
 A number 233 in base 10 notation can be understood
 - All these values are summed.
 
 So:
-```
+
+```text
    233 # decimal
  = 2*10^2 + 3*10^1 + 3*10^0
  = 2*100  + 3*10   + 3*1
 Octal is similar, but uses powers of 8 rather than powers of 10.
 
 So:
-```
+
+```text
    233 # octal
  = 2*8^2 + 3*8^1 + 3*8^0
  = 2*64  + 3*8   + 3*1

exercises/palindrome-products/README.md

 A palindromic number is a number that remains the same when its digits are
 reversed. For example, `121` is a palindromic number but `112` is not.
 
-Given the definition of a palindromic number, we define a palindrome _product_
-to be the product `c`, such that `a * b = c`, where `c` is a palindromic number and
- `a` and `b` are integers (possibly, but _not_ necessarily palindromic numbers).
+Given a range of numbers, find the largest and smallest palindromes which
+are products of numbers within that range.
 
-For example, the palindromic number 9009 can be written as the palindrome
-product: `91 * 99 = 9009`.
-
-It's possible (and indeed common) for a palindrome product to be the product
-of multiple combinations of numbers. For example, the palindrome product `9` has
-the factors `(1, 9)`, `(3, 3)`, and `(9, 1)`.
-
-Write a program that given a range of integers, returns the smallest and largest
-palindromic product within that range, along with all of it's factors.
+Your solution should return the largest and smallest palindromes, along with the
+factors of each within the range. If the largest or smallest palindrome has more 
+than one pair of factors within the range, then return all the pairs.
 
 ## Example 1
 
 Given the range `[1, 9]` (both inclusive)...
 
-The smallest product is `1`. It's factors are `(1, 1)`.
-The largest product is `9`. It's factors are `(1, 9)`, `(3, 3)`, and `(9, 1)`.
+And given the list of all possible products within this range:
+`[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 15, 21, 24, 27, 20, 28, 32, 36, 25, 30, 35, 40, 45, 42, 48, 54, 49, 56, 63, 64, 72, 81]`
+
+The palindrome products are all single digit numbers (in this case):
+`[1, 2, 3, 4, 5, 6, 7, 8, 9]`
+
+The smallest palindrome product is `1`. Its factors are `(1, 1)`.
+The largest palindrome product is `9`. Its factors are `(1, 9)` and `(3, 3)`.
 
 ## Example 2
 
 Given the range `[10, 99]` (both inclusive)...
 
-The smallest palindrome product is `121`. It's factors are `(11, 11)`.
-The largest palindrome product is `9009`. It's factors are `(91, 99)` and `(99, 91)`.
+The smallest palindrome product is `121`. Its factors are `(11, 11)`.
+The largest palindrome product is `9009`. Its factors are `(91, 99)`.
 
 
 To run the tests:

exercises/pangram/README.md

 
 Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma,
 "every letter") is a sentence using every letter of the alphabet at least once.
-The best known English pangram is: 
+The best known English pangram is:
 > The quick brown fox jumps over the lazy dog.
 
 The alphabet used consists of ASCII letters `a` to `z`, inclusive, and is case

exercises/pascals-triangle/README.md

 In Pascal's Triangle each number is computed by adding the numbers to
 the right and left of the current position in the previous row.
 
-```plain
+```text
     1
    1 1
   1 2 1

exercises/perfect-numbers/README.md

 
 The Greek mathematician [Nicomachus](https://en.wikipedia.org/wiki/Nicomachus) devised a classification scheme for natural numbers, identifying each as belonging uniquely to the categories of **perfect**, **abundant**, or **deficient** based on their [aliquot sum](https://en.wikipedia.org/wiki/Aliquot_sum). The aliquot sum is defined as the sum of the factors of a number not including the number itself. For example, the aliquot sum of 15 is (1 + 3 + 5) = 9
 
-- **Perfect**: aliquot sum = number 
+- **Perfect**: aliquot sum = number
   - 6 is a perfect number because (1 + 2 + 3) = 6
   - 28 is a perfect number because (1 + 2 + 4 + 7 + 14) = 28
 - **Abundant**: aliquot sum > number
 - **Deficient**: aliquot sum < number
   - 8 is a deficient number because (1 + 2 + 4) = 7
   - Prime numbers are deficient
-  
+
 Implement a way to determine whether a given number is **perfect**. Depending on your language track, you may also need to implement a way to determine whether a given number is **abundant** or **deficient**.
 
 

exercises/phone-number/README.md

 
 NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as *area code*, followed by a seven-digit local number. The first three digits of the local number represent the *exchange code*, followed by the unique four-digit number which is the *subscriber number*.
 
-
 The format is usually represented as
-```
+
+```text
 (NXX)-NXX-XXXX
 ```
+
 where `N` is any digit from 2 through 9 and `X` is any digit from 0 through 9.
 
 Your task is to clean up differently formated telephone numbers by removing punctuation and the country code (1) if present.

exercises/pythagorean-triplet/README.md

 A Pythagorean triplet is a set of three natural numbers, {a, b, c}, for
 which,
 
-```
+```text
 a**2 + b**2 = c**2
 ```
 
-For example, 
+For example,
 
-```
+```text
 3**2 + 4**2 = 9 + 16 = 25 = 5**2.
 ```
 

exercises/queen-attack/README.md

 So if you're told the white queen is at (2, 3) and the black queen at
 (5, 6), then you'd know you've got a set-up like so:
 
-```plain
+```text
 _ _ _ _ _ _ _ _
 _ _ _ _ _ _ _ _
 _ _ _ W _ _ _ _

exercises/rectangles/README.md

 
 Count the rectangles in an ASCII diagram like the one below.
 
-```
+```text
    +--+
   ++  |
 +-++--+
 
 The above diagram contains 6 rectangles:
 
-```
+```text
 
 
 +-----+
 +-----+
 ```
 
-```
+```text
    +--+
    |  |
    |  |
    +--+
 ```
 
-```
+```text
    +--+
    |  |
    +--+
 
 ```
 
-```
+```text
        
        
    +--+
    +--+
 ```
 
-```
+```text
        
        
 +--+
 +--+
 ```
 
-```
+```text
        
   ++   
   ++   

exercises/roman-numerals/README.md

 these letters have lots of straight lines and are hence easy to hack
 into stone tablets).
 
-```
+```text
  1  => I
 10  => X
  7  => VII

exercises/rotational-cipher/README.md

 
 A `ROT13` on the Latin alphabet would be as follows:
 
-```plain
+```text
 Plain:  abcdefghijklmnopqrstuvwxyz
 Cipher: nopqrstuvwxyzabcdefghijklm
 ```
 Ciphertext is written out in the same formatting as the input including spaces and punctuation.
 
 ## Examples
+
 - ROT5  `omg` gives `trl`
 - ROT0  `c` gives `c`
 - ROT26 `Cool` gives `Cool`

exercises/run-length-encoding/README.md

 
 For example we can represent the original 53 characters with only 13.
 
-```
+```text
 "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB"  ->  "12WB12W3B24WB"
 ```
 
 RLE allows the original data to be perfectly reconstructed from
 the compressed data, which makes it a lossless data compression.
 
-```
+```text
 "AABCCCDEEEE"  ->  "2AB3CD4E"  ->  "AABCCCDEEEE"
 ```
 
 For simplicity, you can assume that the unencoded string will only contain
-the letters A through Z (either lower or upper case) and whitespace. This way 
-data to be encoded will never contain any numbers and numbers inside data to 
+the letters A through Z (either lower or upper case) and whitespace. This way
+data to be encoded will never contain any numbers and numbers inside data to
 be decoded always represent the count for the following character.
 
 

exercises/saddle-points/README.md

 
 So say you have a matrix like so:
 
-```plain
+```text
     0  1  2
   |---------
 0 | 9  8  7

exercises/scrabble-score/README.md

 
 You'll need these:
 
-```plain
+```text
 Letter                           Value
 A, E, I, O, U, L, N, R, S, T       1
 D, G                               2
 ```
 
 ## Examples
+
 "cabbage" should be scored as worth 14 points:
 
 - 3 points for C
 - = 14
 
 ## Extensions
+
 - You can play a double or a triple letter.
 - You can play a double or a triple word.
 

exercises/secret-handshake/README.md

 You and your fellow cohort of those in the "know" when it comes to
 binary decide to come up with a secret "handshake".
 
-```
+```text
 1 = wink
 10 = double blink
 100 = close your eyes

exercises/simple-cipher/README.md

 would return the original "iamapandabear".
 
 Given the key "ddddddddddddddddd", encoding our string "iamapandabear"
-would return the obscured "lpdsdqgdehdu"
+would return the obscured "ldpdsdqgdehdu"
 
 In the example above, we've set a = 0 for the key value. So when the
 plaintext is added to the key, we end up with the same message coming

exercises/space-age/README.md

    - Neptune: orbital period 164.79132 Earth years
 
 So if you were told someone were 1,000,000,000 seconds old, you should
-be able to say that they're 31 Earth-years old.
+be able to say that they're 31.69 Earth-years old.
 
 If you're wondering why Pluto didn't make the cut, go watch [this
 youtube video](http://www.youtube.com/watch?v=Z_2gbGXzFbs).

exercises/spiral-matrix/README.md

 
 ###### Spiral matrix of size 3
 
-```plain
+```text
 1 2 3
 8 9 4
 7 6 5
 
 ###### Spiral matrix of size 4
 
-```plain
+```text
  1  2  3 4
 12 13 14 5
 11 16 15 6

exercises/sum-of-multiples/README.md

 
 The sum of these multiples is 78.
 
-Given a number, find the sum of the multiples of a given set of numbers,
-up to but not including that number.
-
 
 To run the tests:
 

exercises/tournament/README.md

 Based on an input file containing which team played against which and what the
 outcome was, create a file with a table like this:
 
-```
+```text
 Team                           | MP |  W |  D |  L |  P
 Devastating Donkeys            |  3 |  2 |  1 |  0 |  7
 Allegoric Alaskans             |  3 |  2 |  0 |  1 |  6
 
 Your tallying program will receive input that looks like:
 
-```
+```text
 Allegoric Alaskans;Blithering Badgers;win
 Devastating Donkeys;Courageous Californians;draw
 Devastating Donkeys;Allegoric Alaskans;win
 
 The result of the match refers to the first team listed. So this line
 
-```
+```text
 Allegoric Alaskans;Blithering Badgers;win
 ```
 
 
 This line:
 
-```
+```text
 Courageous Californians;Blithering Badgers;loss
 ```
 
 
 And this line:
 
-```
+```text
 Devastating Donkeys;Courageous Californians;draw
 ```
 
 For more detailed info about the Java track see the [help page](http://exercism.io/languages/java).
 
 
+
 ## Submitting Incomplete Solutions
 It's possible to submit an incomplete solution so you can see how others have completed the exercise.

exercises/transpose/README.md

 
 Roughly explained, the transpose of a matrix:
 
-```
+```text
 ABC
 DEF
 ```
 
 is given by:
 
-```
+```text
 AD
 BE
 CF
 
 Therefore, transposing this matrix:
 
-```
+```text
 ABC
 DE
 ```
 
 results in:
 
-```
+```text
 AD
 BE
 C
 
 And transposing:
 
-```
+```text
 AB
 DEF
 ```
 
 results in:
 
-```
+```text
 AD
 BE
  F
 ```
 
 In general, all characters from the input should also be present in the transposed output.
-That means that if a column in the input text contains only spaces on its bottom-most row(s), 
+That means that if a column in the input text contains only spaces on its bottom-most row(s),
 the corresponding output row should contain the spaces in its right-most column(s).
 
 

exercises/triangle/README.md

 
 Determine if a triangle is equilateral, isosceles, or scalene.
 
-An _equilateral_ triangle has all three sides the same length.<br/>
+An _equilateral_ triangle has all three sides the same length.
+
 An _isosceles_ triangle has at least two sides the same length. (It is sometimes
 specified as having exactly two sides the same length, but for the purposes of
-this exercise we'll say at least two.)<br/>
+this exercise we'll say at least two.)
+
 A _scalene_ triangle has all sides of different lengths.
 
 ## Note
 
-For a shape to be a triangle at all, all sides have to be of length > 0, and 
-the sum of the lengths of any two sides must be greater than or equal to the 
+For a shape to be a triangle at all, all sides have to be of length > 0, and
+the sum of the lengths of any two sides must be greater than or equal to the
 length of the third side. See [Triangle Inequality](https://en.wikipedia.org/wiki/Triangle_inequality).
 
 ## Dig Deeper
 
-The case where the sum of the lengths of two sides _equals_ that of the 
-third is known as a _degenerate_ triangle - it has zero area and looks like 
+The case where the sum of the lengths of two sides _equals_ that of the
+third is known as a _degenerate_ triangle - it has zero area and looks like
 a single line. Feel free to add your own code/tests to check for degenerate triangles.
 
+
 To run the tests:
 
 ```sh

exercises/trinary/README.md

 The last place in a trinary number is the 1's place. The second to last
 is the 3's place, the third to last is the 9's place, etc.
 
-```bash
+```shell
 # "102012"
     1       0       2       0       1       2    # the number
 1*3^5 + 0*3^4 + 2*3^3 + 0*3^2 + 1*3^1 + 2*3^0    # the value

exercises/twelve-days/README.md

 
 Output the lyrics to 'The Twelve Days of Christmas'.
 
-```
+```text
 On the first day of Christmas my true love gave to me, a Partridge in a Pear Tree.
 
 On the second day of Christmas my true love gave to me, two Turtle Doves, and a Partridge in a Pear Tree.

exercises/two-fer/README.md

 
 `Two-fer` or `2-fer` is short for two for one. One for you and one for me.
 
-```
+```text
 "One for X, one for me."
 ```
 
 If the given name is "Alice", the result should be "One for Alice, one for me."
 If no name is given, the result should be "One for you, one for me."
 
-
 ## Test-Driven Development
 
 As programmers mature, they eventually want to test their code.

exercises/word-count/README.md

 
 For example for the input `"olly olly in come free"`
 
-```plain
+```text
 olly: 2
 in: 1
 come: 1
 ```
 
 
-
 To run the tests:
 
 ```sh

exercises/word-search/README.md

 
 For example:
 
-```
+```text
 jefblpepre
 camdcimgtc
 oivokprjsm

exercises/wordy/README.md

 
 Parse and evaluate simple math word problems returning the answer as an integer.
 
-
 ## Iteration 1 — Addition
 
 Add two numbers together.
 
 Handle large numbers and negative numbers.
 
-
 ## Iteration 2 — Subtraction, Multiplication and Division
 
 Now, perform the other three operations.
 
 5
 
-
 ## Iteration 3 — Multiple Operations
 
 Handle a set of operations, in sequence.
 
 15  (i.e. not 9)
 
-
 ## Bonus — Exponentials
 
 If you'd like, handle exponentials.
 32
 
 
-
 To run the tests:
 
 ```sh