).Constructors have dubbed this type of puzzle a Schrödinger or quantum puzzle after the famous paradox of Schrödinger's cat, which was both alive and dead at the same time.Since Farrell's invention of it, nine other constructors—Patrick Merrell, Ethan Friedman, David J. Kahn, Damon J. Gulczynski, Dan Schoenholz, Andrew Reynolds, Kacey Walker and David Quarfoot (in collaboration), and Ben Tausig have made use of a similar trick.