I give them 3 typefaces with missing letters each semester. This semester we compared Caslon, Kabel, and this typeface. They analyze the existing letters and then attempt to render what they think the missing letters look like. The letters missing were e, g, k, r, s, t, x. Without those letters, there was little in the way of clues to go by and as a result made them aware of the unique anatomy of typefaces. It was easier to find clues in the other two, but even then, there are unique features to compare and discuss.