Figure 1.

(A) schematic diagram of the geometrical principle of linear perspective. Four cubes are shown at (A) in plan-view; At (B) is shown a light barrier with a centrally located pinhole; (C) shows a plane on which the light rays, a subset of which are indicated by dashed lines, travelling from the cubes at A are projected; (D) shows an elevation view of the scene as rendered from the projection.