This is a collection of informative extracts from Gardners' ''Scientific American'' column. Each brain-teasing article has been updated to include new mists, new ideas, and new solutions. Highlights include two new chapters-one on pi and poetry, one on minimal sculpture-and intriguing forays into time reversal, forms of fractions and magic, and an imaginary ''Math Zoo'' with its own publication, ''ZOO-NOOZ''.