('red', 'green', 'blue', 'yellow')
('red', 'green', 'yellow', 'blue')
('red', 'blue', 'green', 'yellow')
('red', 'blue', 'yellow', 'green')
('red', 'yellow', 'green', 'blue')
('red', 'yellow', 'blue', 'green')
('green', 'red', 'blue', 'yellow')
('green', 'red', 'yellow', 'blue')
('green', 'blue', 'red', 'yellow')
('green', 'blue', 'yellow', 'red')
('green', 'yellow', 'red', 'blue')
('green', 'yellow', 'blue', 'red')
('blue', 'red', 'green', 'yellow')
('blue', 'red', 'yellow', 'green')
('blue', 'green', 'red', 'yellow')
('blue', 'green', 'yellow', 'red')
('blue', 'yellow', 'red', 'green')
('blue', 'yellow', 'green', 'red')
('yellow', 'red', 'green', 'blue')
('yellow', 'red', 'blue', 'green')
('yellow', 'green', 'red', 'blue')
('yellow', 'green', 'blue', 'red')
('yellow', 'blue', 'red', 'green')
('yellow', 'blue', 'green', 'red')