Dividing brownies

Recently, the "9 dot puzzle" was used by Bob to illustrate "thinking out of the box."
Yesterday, on the radio show Car Talk, the "brownie puzzle" was given along with
two solutions -- a thinking out of the box solution as well as a thinking in the box solution.

Puzzle: Mom made brownies in a rectangular baking dish. Dad cut a rectangle of
brownies out of the interior of the dish but not touching the sides of the dish.
(Dad's rectangle may be at an angle to the dish, it may be one-third of the size of the
dish, one seventh of the size etc. ) How does mom use one stroke of the knife to
ensure that her two children share the brownies equally?

The TOB solution: She holds the knife blade parallel to the table when cutting the
brownies in half.

The TIB solution: She holds the knife blade perpendicular to the table when
cutting -- hitting the center point of the baking dish as well as the center point
of the missing rectangle.

That's over my head. But I just wanted to say that I love "Car Talk." It is a National Public Radio program (U.S.). People call in and describe their car problems. The hosts try to figure out those problems. But the thing is, the hosts are brothers who crack each other up. I guess you'd have to be there.