A masterpiece of popularisation of mathematics, by Steven Strogatz in the NYT: fingerprinting, the index theorem and works by L. S. Penrose, “Dermatoglyphic topology,” Nature, Vol. 205 (1965), pp. 544–546, and R. Penrose, “The topology of ridge systems,” Annals of Human Genetics, Vol. 42 (1979), pp. 435–444.