Figure 1. Tasks and stimuli for the study.

Representative stimuli and responses for two of the drawing conditions. In mark making, the name of a geometric figure and a direction for drawing it are presented. Blind drawing (not shown in the figure) has exactly the same stimuli, but no response is observable on the drawing tablet. In copying, an object and a starting point for drawing are indicated, and the subject creates a copy of the object in the space to the right, with the object continually in view.