Mr. and Mrs. Merlin are bored with their pet turtle, so Mr. Merlin turns it into a bird. The bird flies into a tree, so he turns it into a monkey. The monkey wreaks havoc on a bicycle, so he turns it into a camel. The camel eats all the oranges on the orange tree, so he turns it into an elephant. The elephant frightens Mrs. Merlin, so Mr. Merlin turns it back into a turtle. Readers help out with the transformations by lifting increasingly complex flaps and watching the head of one animal suddenly appearing on the body of another. The drawings, rendered in pen and ink and filled in with color film, look like comic strips; their muted colors and ridiculous characters--particularly the hapless, long-nosed wizard--are straight out of the funny pages. True to the genre, they display an uncommon economy of means, perfectly balanced between telling a story and telling a joke: The bicycle leaning against the wall of Mr. Merlin's medieval castle in one picture turns out to be ideal for the monkey in the next. The humor is never pushy and always on target.