Triangles

At a glance, one can see that these jaunty and appealing concept books take their topics seriously: all are shaped like their respective titles. The five spreads in each depict children from various cultures engaged in such activities as playing checkers and setting out a picnic blanket (squares); climbing a mountain and sailing a boat (triangles); playing ball and riding a unicycle (circles). In addition to its primary subject, each illustration features several objects of the designated shape for sharp-eyed youngsters to identify. The colors are vibrant, the kids are obviously having fun, the various shapes are clearly--and sometimes ingeniously--represented: in short, this winning trio carries out its task in grade-A shape. Ages 1-5. (Mar.)