The exercise requires students to identify among 10 bite marks, two that were made by the same person. To make the task easier and more realistic, one of the two marks may be designated as the "evidential mark," and the other nine marks are all designated as bite marks of potential suspects. A sheet of heavy leather about 1/8 inch thick is cut into pieces about 2 x 2 1/2 inches. These are then soaked overnight in a basin of water to soften the leather. Volunteer students are instructed to bend the leather pieces and bite hard so as to obtain an impression of both upper and lower teeth. The leather pieces are straightened out or flattened and allowed to dry. The teeth marks remain as indentations. Using fingerprint ink and roller, the leather plaques are inked thoroughly, producing a blackened surface with the indented teeth marks appearing in light colored contrast. After a few minutes to allow the ink to dry, the bite marks are arranged upon the glass plate of an electrostatic copier. Once the best contrast is achieved, copies are made for the members of the class. Class members can use any technique they choose to make the comparisons. 3 figures