Press the flag! Use the arrow keys to rotate! The shape is an optical illusion by M.C. Escher. It is impossible to make in real life, so some visual tricks have to be used.
These images were created in the orthographic view mode of Blender. Blender is a 3D modelling program which is compatible with all software types. Orthographic view is a function which makes similar objects at different distances the same size. This allows the two end prongs in this figure to match up and complete the shape without physically touching.
