You’ve probably had your eyesight tested. In these exams, you’re asked to cover one eye, then read out loud the letters from an eyesight chart called a Snellen chart. The letters are arranged in 11 rows and include only the letters C, D, E, F, L, N, O, P, T, Z.

The first row has one letter in a very large font. As you move down, the number of letters in each row increases by one and the font size of the letters decreases, ending with a row of 11 letters in a very small font. Your ability to read the letters accurately measures your visual acuity. Create an eyesight-testing chart similar to the Snellen chart (http://en.wikipedia.org/wiki/Snellen_chart) used by medical professionals. The chart is meant to be read from 20 feet away, so scale the fonts accordingly, given that you’re sitting close to your screen.