On 26/12/2016 14:04, Moron Watch wrote:

Any fool can tell if a floor is sloping by dropping a ball on it or spilling a
liquid, just as they could by using a spirit level.

The question being posed all those years ago is how much it
would have to slope for you to notice it without the aid of tools
or apparatus of any kind;either deliberately or by accident.

I genuinely think that 2cm in 4m would be noticeable. Maybe not just
walking along it, but when you put a run of kitchen units or a wardrobe
on it.