Students rub charcoal on the bottom of one of their sneakers. Then,that sneaker is used to make a sneaker print on a piece of white paper. Thereafter, a close-fitting rectangle is drawn around the sneaker print and the length and width of the print are measured and recorded next to the print. Next, the area of the rectangle is calculated, which indicates the smallest rectangular area that this size sneaker can step into. Then each student writes their name on the back of their paper, and they are collected. In closing, the instructor shuffles the papers, and then one at a time, holds up each sneaker print, describes it in terms of its length, width, and rectangular surface area, moments before the class guesses whose print it is. The name on the backside is then revealed!