In the world of tiles there was a failure and they began to act not dosed, as before, but at random. Until the program is fixed, it is necessary to manually control the number of squares on the white field, and there must be a minimum number of squares. The dotted designation of the square means the place where the next block will fall. Do not allow the tower to grow to the upper boundary line. Left-click the mouse to install the tiles, and by clicking on the right, rotate the structure. If there are yellow or red squares - these are lasers, they delete entire rows or groups, which will slightly simplify the task in minimalized.