This puzzle is something for long winter evenings. Begin with the pattern shown in the image with the big square on the laft hand side. The aim is to move the large square all the way to the right. No stone may be lifted or removed in the process. Only moving is allowed.
But beware, it is advisable to take plenty of time to solve the puzzle. The puzzle looks easier than it is.

P.S..
The solution can be found in the attached PDF document. But take a look first before you freak out.