Smarty pants

I was going to be oh so clever in some way relating to this:

In any right triangle, the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares whose sides are the two legs (the two sides that meet at a right angle).
Then I realised it's not a bloody right angled triangle.
Doh.
It is in fact my book hook, the largest bookmark known to mankind.
I have to say though I do love it!