Parted Square Puzzle - Solution
The Puzzle:

Each has a different pattern of holes.
Which three of them can form an opaque (non-transparent) square when stacked on top of each other?
You are allowed to rotate or flip the squares.

Author: Peter Grabarchuk
This Puzzle © 2007 Peter Grabarchuk. All Rights Reserved.
More from Peter Grabarchuk at PeterPuzzle.com
Our Solution:
The solution is shown in this illustration:

Author: Peter Grabarchuk
This Puzzle © 2007 Peter Grabarchuk. All Rights Reserved.

Author: Peter Grabarchuk
This Puzzle © 2007 Peter Grabarchuk. All Rights Reserved.
Puzzle Author: Grabarchuk, Peter
See this puzzle without solution