The document defines key terms related to depth, dimensions, and perspective techniques in visual art. It explains that two-dimensional images have height and width but no depth, while three-dimensional objects have all three. Perspective is a technique to make two-dimensional surfaces appear three-dimensional through the use of foreground, middle ground, background, overlapping objects, size variation, converging lines, and a single vanishing point where those lines meet on the horizon. The document then asks if a specific work of art by Leonardo uses perspective and identifies its vanishing point.