By clicking anywhere in the applet you can define (and redefine) the missing square. The "exponent" parameter defines n, for a 2n×2n board. The number can be changed by clicking a little off it central line.
Proof
Divide the board into 4 equal squares. The missing square belongs to one of the four. The other three form an L-shaped tromino, which, being a rep-4 tile, can be tiled by smaller copies of itself, which, in turn, can be tiled (if necessary) by smaller copies of themselves, and so on. Every size board can be treated in this manner. In particular, we can apply this step to the remaining square where the small missing square is located. The process will stop when n = 1, i.e., when a 2×2 square is reached that conisists of a single L-tromino and the missing square.
References
- S. Golomb, Two Right Tromino Theorems, in The Changing Shape of Geometry, edited by C. Pritchard, Cambridge University Press, 2003
- S. Golomb, Polyominoes, Princeton University Press, 1994
Copyright © 1996-2009 Alexander Bogomolny