[I was asked this puzzle by Vlad Rusu, who in turn heard it from Grigore Rosu and family]
Two arbitrary rectangles are placed to form an “L”. That is, the lower left-hand corner of the two rectangles share the same point. (What I’m trying to say is that there’s an “L” whose “I” and “_” parts have arbitrary widths and heights.) Using only a (pen and a) straightedge (that is, no measuring device and no compass), figure out a way to, with a single straight cut, divide the “L” into two pieces of equal area.