Impossible Triangle Illusion
When most people initially see an impossible triangle, they don’t always realise that it is in fact an impossible shape. It simply looks like a regular triangle but in 3D, until you take a much closer look at it.
The reason that this particular image of an impossible triangle is great is due to the moving ball that follows a track around the object, highlighting the unnatural nature of this shape.
It soon becomes apparent that the right angled sides keep changing orientation in ways that could never join up to form a 3D triangle in the real world.
Although, there are ways to apparently construct a 3D triangle in the real world. Sadly, they all rely on three unconnected edges being viewed on the correct angle to give the illusion on an impossible triangle. It’s kind of an illusion within an illusion type thing.
Another name for the impossible triangle is the ‘Penrose Triangle‘ or ‘Penrose Tribar’ and was first created by Swedish artist Oscar Reutersvärd in 1934. Many people will recognise the use of impossible triangles and other shapes in the work of the famous artist M.C. Escher.
How to draw an Impossible Triangle
Here is your opportunity to learn a party trick. You can offer to draw something that the person, or group, will be able to see and describe but not understand. When someone takes you up on this, you can draw an impossible triangle, because this will be something that they can see (because you’ve drawn it), something they can describe (they will describe it as a triangle), yet they will not be able to make sense of it if you ask them to follow the edges with their finger. Make them trace along the edges with their finger, in a similar way to the way the ball is moving in the image above.
Here’s how to draw an impossible triangle: