Each poem is readable frontwards and backwards, with each line acting as its own unit. (This means some of the lines are quite short, of course.)
And the front and the back version of each poem tells the fairy tale from a different perspective. My favorite? The Hansel and Gretel one:
Fatten up, boy! Don't you like prime rib? Then your hostess, she will roast you goose. Have another chocolate. Eat another piece of gingerbread. When you hold it out, your finger feels like a bone. Fatten up. Don't keep her waiting...
Keep her waiting. Don't fatten up. A bone feels like your finger when you hold it out. Eat another piece of gingerbread, Have another chocolate - Goose! Then your hostess, she will roast you like prime rib. Don't you fatten up, boy!