How to Do a Back Handspring. The back handspring is a basic building block for many gymnastics or cheerleading routines. To do a back handspring, you have to fall backwards, land upside-down on your hands, and push upwards to land back on your feet.
Generally, they take the form of puzzles which must be solved. The puzzles may be visual, as in the case of pattern recognition games, or they may involve plays on words and numbers. Logic puzzles are also brain teasers.
Any kind of grid that deceives a person's vision. The two most common types of grid illusions are the Hermann grid illusion (1870) and the scintillating grid illusion (1994). The first is characterized by ghostlike grey blobs perceived at the intersections of a white (or light-colored) grid on a black background.