PURPOSE: Classic impossible triangle illusion with a twist.
DESCRIPTION: The classic impossible triangle is constructed from three orthogonal aluminum bars. The front bar has a cutout which is aligned with the rear bar so that the triangle appears closed when viewed from a particular point (or along a s hort line), forming an impossible figure.
This gizmo bothers people more when it is set up with a pendulum apparently swinging through the "solid" metal of the triangle. The photograph shows the triangle with the pendulum at its equilibrium position along with the view of the triangle from an appropriately positioned TV camera.
REFERENCES: (PIRA 6J11.50)
SETUP TIME: None.
Go back to Lecture-Demonstration Home Page.