During our vacation in Israel, I had occasion to use many toilet flush handles. It seems to me that Israel (and perhaps all of Europe as well) has hit upon the precise sweet spot in its bureaucratic regulations of these handles. First, you must understand that almost every toilet has two handles. One of these produces a much more prodigious flush than the other. Second, it appears that anyone who knows about the two-handle system can figure out which handle will produce the larger flush.
Now you may find my second point puzzling, unless you already know the truth: there is an unbelievable variety in the design of these handles. Artists and designers have been given free-reign by the bureaucrats to make the handles look any way they want, as long as they are there, and their separate functions can be inferred. Let art reign! At least, when it comes to clever functional design.