It doesn't appear that the combination of any two angles (of two pieces) will make a right angle and there is only one right angle per piece, so I would start there. Each corner of the square must be a right angle. Otherwise (in case I'm wrong) fit the different pieces together to see if you can find any other right angles.
October 16th 2006, 08:43 PM
I assume that the four pieces are congruent.
Then they must fit together like this: