Theoretical plastic surgery—

Three lengths (actually -20/5 = 4 > 3 is not needed)

Three widths (actually not used-15/5 = 3)

Three highs (the most economical packaging-the theoretical minimum dosage is: (15 * 4) * 20+(15 *15) * 2 =1650cm2).

Theoretical anomalies-more, but not in practice!