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