Where Does The Hole Come From?

I haven't been able to figure this out. Can someone else tell me how this is done?

http://home.ripway.com/2003-7/16532/Geometry.jpg

Woooo....that is messed up. Now I'm not going to be able to sleep!

Hold a ruler up to the angled line on both pictures.

In the top one you will see that is actually not straight it is convex and the area caused by the amount of deviation results in 1 less square.

In the bottom picture where the angled line is straight the extra square is shown as a hole.

Don't think I explained that too well, but do the ruler on the angled lines and you'll see one is straight and one is not and that's why.

Wait....I used to know this one. As I recall it had something to do with the hypotenuse of the left degree up-angle of the third triangle as it is opposed by the light green odd-box when juxtaposed sideways and slightly above (or was it below?) the red thingamajingy.....or something like that.


...and to think my 7th grade geometry teacher said I would never amount to anything. HA!

I don't see the problem here. It's obvious that if you move the gold shape to join with the light green shape like it is in the lower image you have to have a blank square on the graph.

Hi, no Nix has nailed it, it is an optical illusion, to see it count down 4 squares(?) vertical then go across 7 squares (?) for the first image note the angle to the top of the ? square. Now on the second count down 12 (?) squares and then across 7 (?) squares, notice the difference.