IN SHORT

BOOKS OINK Arthur Geisert (Houghton Mifflin, $13.95, all ages) It's hard to believe that a quiet little almost wordless picture book in muted colors (black and white, with pink pigs) could be so delectably funny. The text's one word is ''Oink,'' and it stretches like elastic or shrivels into tiny print to express a dozen different, hilarious moods. A litter of piglets sneaks off on a grand adventure while Mama sleeps. Tentative, then bolder, they leap off a cliff into an apple tree and gobble happily-but there's oink to pay when Mama catches them. Visual understatement works brilliantly here, drawing the reader into the action. The eight little piggies are delightfully por-cine in Geisert's delicate etchings. But every human child will recognize the impulse toward naughtiness and the sobering comeuppance that follows. A -