I unpublished this the other day but have been asked by another user to put it back up...enjoy
The Penrose triangle, also known as the tribar is an impossible object. It was first created by the Swedish artist Oscar ReutersvÃ¤rd in 1934. The mathematician Roger Penrose independently invented and popularised it in the 1950s, describing it as "impossibility in its purest form". It features prominently in the works of artist M. C. Escher, whose earlier depictions of impossible objects partly inspired it.
Step 1: Items Used
1. Balsa wood
2. Super Glue
3. A little bit of magic
Step 2: Method
This illusion is all smoke and mirrors. It is obviously a trick of camera angles.
You can make this a big or as small as you want but, I have found that a small one is easy and effective. Cut 3 pieces of balsa wood about 5 cm long, each end should be right-angled. Name each piece: A, B and C. Take piece A and B, glueing at the end so that they form a right angle. Take part C and cut a 45 degree angle at the end so that the longest side is the same length.
See below for plan
Step 3: The Illusion Shown
The best way to see this working is to look at this video:
Penrose Triangle Revealed
Enjoy....sorry about the republish but it was a request