possible_colors = [0xff0000, 0x00ff00, 0x0000ff, 0xffff00, 0x00ffff, 0xffffff]
good_color = 0 # We can default to black...
possible_colors.each do |c|
  if colors_diff_ok? c, my_color
    good_color = c
    break
  end
end

Finding a good color - usage

color

Ruby