Einstein 1: Ruby's Array#permutation Method

permutation.rb

colors = [:white, :yellow, :blue, :red, :green].permutation
# => #<Enumerator: [:white, :yellow, :blue, :red, :green]:permutation>

colors = [:white, :yellow, :blue, :red, :green].permutation.to_a[0]
# => [:white, :yellow, :blue, :red, :green]

colors = [:white, :yellow, :blue, :red, :green].permutation.to_a[1]
# => [:white, :yellow, :blue, :green, :red]
colors = [:white, :yellow, :blue, :red, :green].permutation.to_a[2]
# => [:white, :yellow, :red, :blue, :green]