Green and Blue are best friends. But . . . who is the bestest? Green builds a bigger, better shell. And then Blue builds a biggerer, betterer shell!Uh-oh - I think we can guess where this is going.Who, or what, will ultimately triumph?This furiously fast-paced and witty picture book warns of the dangers of comparing yourself to others, especially your friends!Packed with lots of visual humour, children will hoot with laughter at Blue and Green's ever-growing silly shells.From Clive Penguin illustrator and creator of the Agent Harrier graphic novel series, Ben Sanders.