It's been a long time since I was there, so maybe this has changed, but when I lived in Amsterdam in the early '80's, most of the toilets that I encountered had one very noticeable difference to the ones I was used to in England; namely, instead of the entrance to the waste pipe being situated towards the back of the bowl, directly underneath the user's seated ass, it was towards the front of the bowl. So what was under the user's ass? A PORCELAIN SHELF, which unsurprisingly was known among my friends as the Shit Shelf.
I have no idea why Dutch toilets were/are designed this way. Perhaps Dutch people are particlularly keen on examining their solid waste, since that's all the Shit Shelf seems good for. Indeed, it fulfils that purpose admirably, since fresh turds land there and then perch happily, awaiting the next step of their journey with benign interest (or so it seemed to me). And that next step was, I suppose, more fun than a freshly-laid turd can reasonably expect to have: when such a toilet is flushed, the water from the cistern is expelled from the back of the bowl onto the shelf, forcing the contents of the shelf forward until they drop down into the main body of the bowl, thus creating a sort of fecal waterslide.
Wheeee!!!!