It is fair to show a good design of a tap control - actually a shower control. I came across this one in a hotel in the Lake District (UK). It has two handles:
- the top one for the temperature and
- the bottom one for the water pressure
It has labels ON/OFF on the top and COLD/HOT under the bottom handle. The labels are in gray over the shiny silver and not visible enough. It would be nice to have some universal labels (like red/blue for temperature and something like increasing number of drops from 0 to 5 for pressure) for non English speakers (since it is used in a hotel), but other than that it is a nice shower control.