dontdothisathome.rb

#!/usr/bin/env ruby

def append(array, n)
  return array if n < 0
  append(array, n-1)
  puts "shit #{n}"
end

p append([], 3)

# 
append([], 3) #=> print 3         / Runs last
  -> append([], 2) #=> print 2    / Runs third
    -> append([], 1) #=> print 1  / Runs second
      -> append([], 0) #=> return / Runs first