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