About

Rubik's Fifteen is a type of sliding piece puzzle. It consists of 17 tiles in a 5x5 square. On the middle three columns there are levers which can move the 4 tiles in a column up or down one square. On the middle three rows there is one large lever that moves the 3x4 tiles left or right. On the top and bottom row there are also levers, but these will only work if there are 4 tiles in the row, i.e. only if all the column levers are up does the top row lever work, only if they are all down does the bottom row lever work. The 15 tiles are numbered 1-15 in Roman numerals, and of the remaining two tiles one has an asterisk, one is black. The aim is to build a 4x4 square of the numbers in order with the asterisk where 16 would be. On the back of the puzzle is a window showing the middle 3x3 square of tiles. The back of the 15 numbered tiles have the same numbers as the front, the other two tiles have a zero on the back. As a separate puzzle you can make a magic square on the back. It is clearly impossible to do this if the front is solved, but if you can solve the front the same method suffices to solve the back. The puzzle was patented by Ernő Rubik on 18 September 1984, US 4,471,959, but there is an earlier Hungarian patent from 1 September 1980, HU2154/80. A related but much more difficult puzzle is 'It' / Tsukuda's Square. Rubik's Fifteen is easier, because it has more levers and therefore less restrictive movement of the tiles. If your browser supports JavaScript, then you can play Rubik's Fifteen by clicking the link below: