Slide the puzzle tiles within a 3x3
tray to a pattern which allows you to go from red box to
blue one along some green path so that you will always
step from one small box to adjacent one horizontally and
vertically, but never diagonally. Keep in mind that not
all green boxes should form the path between the red and
blue ones, but to fully accomplish the whole task tile 9
should go into a vacant place within the puzzle tray.
Every tile in the tray can slide to an adjacent free
space when you simply click the tile. Clicking tile 9
you can get it in or out the tray.