Nim game

You are encouraged to solve this task according to the task description, using any language you may know.
Nim is a simple game where the second player ─── if they know the trick ─── will always win.



The game has only 3 rules:

   start with   12   tokens
   each player takes   1,  2,  or  3   tokens in turn
  the player who takes the last token wins.


To win every time,   the second player simply takes 4 minus the number the first player took.   So if the first player takes 1,   the second takes 3 ─── if the first player takes 2,   the second should take 2 ─── and if the first player takes 3,   the second player will take 1.



Task

Design a simple Nim game where the human player goes first, and the computer always wins. The game should enforce the rules.




[12, 8, 4].each do |remaining|
  puts "There are #{remaining} dots.\nHow many dots would you like to take? "
  unless (num=gets.to_i).between?(1, 3)
    puts "Please enter one of 1, 2 or 3"
    redo
  end
  puts "You took #{num} dots, leaving #{remaining-num}.\nComputer takes #{4-num}.\n\n"
end
 
puts "Computer took the last and wins."
 