@finitebaffle as further visual aids, here are the detergent compartments for my current and old laundry machine, and the programme display of my current laundry machine. See image descriptions for details.

But these are just 2 of an endless variation of designs I guess, though I think most laundry machines have similar markings.

One thing to note btw is that you shouldn't fill the fabric softener above the max level, because you'll trigger the Pythagorean siphon mechanism that would drain the entire compartment. Usually this happens when the machine adds water to it during the appropriate cycle (which I assume is the Rinse cycle? not sure actually). It's an interesting physics principle: https://youtu.be/Cg8KQfaT9xY

@fesshole #FessholeExplained