## 70 They don’t fit

The story At University of Chicago, my physics professor (structure of matter course) tricked us with a priceless lesson. The homework solution was not an exact answer. We were to place sixteen readings into a four-by-four table so that they filled a consistent progression of energy levels. It was easy to sort the numbers into columns such that each number was a fixed step lower than the number above it—except for the last column. After I filled three columns, it was impossible to arrange the remaining four numbers to match the pattern. In discussing the homework solution, we students complained, …