Tic-Tac-Toe in Ruby

ttt.rb

#!/usr/bin/env ruby

def winner_is(winner)
  puts "*Time passes...*"
  if winner == :computer
    puts "I win!"
  else
    puts "OK, you win this one."
  end
end

puts "Let's play Tic-Tac-Toe!"
if rand(2) == 1
  puts "I'll go first."
  puts "I put an X in the center."
  winner_is(:computer)
else
  puts "You go first!"
  print "Do you put an X in the center? (Y|n): "
  if gets.strip =~ /^no?$/i
    winner_is(:computer)
  else
    winner_is(:human)
  end
end