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If you are a pedant with a steady hand, hours of free time and an unhealthy interest in molecules, models and Sellotape, then rush out to buy Molecular Origami by Robert M. Hanson (University Science Books, 拢21.95/$22 pbk, ISBN 0 935 70230 X). Simply remove a page (they are all perforated), cut out the pattern and start folding. Each pattern comes complete with chemistry questions to set students thinking. The book contains patterns for models of more than 70 molecules, although the relationship with molecular structure is sometimes difficult to appreciate. If you鈥檝e never puzzled over the shape of a dodecaborane ion, you will now.