Reading about crayons will never rival actually coloring with them; nevertheless, here's a book of simple rhymes about what crayons ``say'' to a small girl: ``Brown sings, `Play,/Mud-pie day./' Blue calls, `Sky,/Swing so high.' '' It's a playful idea, executed with verses keyed to the lives of preschoolers. The two-liners—two or three words each—have little rhythm or imagery to recommend them, but like jump-rope rhymes, they will inspire chanting along. Karas's pictures depict comically fleshed-out stick-figures swinging in the clouds, confronting owls, and staring down ghosts. (Picture book. 2-4)