by Serhiy Grabarchuk
Divide the shape at the left into two congruent parts. They must be identical in size and shape, and may be rotations and/or even reflections of each other.
To show these parts mark their respective single squares in two different colors. To change the color of a square just click it.
When you get the solution a special message will automatically inform you about it. If you don't want to get the message accidentally choose the option "Don't display the message". But in either case you may check your solution - just click the "Check" button at any time.