Take awhile to think about how this could possibly work? There is a missing square in the second optical illusion drawing, but the peices are exactly the same! Aren't they?
Explanation: Actually the shapes in this optical illusion drawing are NOT the same। The two triangles are actually different from eachother in each picture। In fact, the graph paper may even be slightly stretched to enhance this optical illusion. The hypotenuse(that's the diagonal line) of the triangles are actually different. Depending on which picture you are looking at, they slightly bow in and out. In addition, they are spaced a little farther apart, but your eye tends to follow the black lines as if nothing has changed. This might be a great page to print out, and cut with scissors to more carefully study this optical illusion.