use 'width' and 'height' URL parameters to change both, there is a recursion limit :)
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | | | | | + + + +--+ +--+ + +--+--+--+--+--+ + +--+ | | | | | | | | | | | | | + +--+ + +--+ + + + + + + + + + + + | | | | | | | | | | | | + + +--+ + + +--+--+--+--+ +--+--+--+--+ + | | | | | | | + +--+ + + +--+--+--+--+--+--+ +--+--+--+ + | | | | | | | | | | + +--+ + +--+ + +--+ + + + + + +--+ + | | | | | | | | | | | | +--+ + + + +--+ + +--+ + + + +--+--+--+ | | | | | | | | | | + +--+ + +--+ +--+ + +--+--+--+--+--+--+ + | | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+