An infinitely strange perspective

• Parallel lines in 3D space converge in images.
• The line of the horizon is formed by `infinitely' distant points (vanishing points).
• Any pair of parallel lines meet at a point on the horizon corresponding to their common direction.
• All `intersections at infinity' stay constant as the observer moves.

The effects can be modelled mathematically using the `linear perspective' or a `pin-hole camera' (realized first by Leonardo?)