Dial idea

I thought of a new cool feature last night - what if, instead of switching instantaneously between two settings, the leds would 'fade'/count down or up to the desired level (within 0,5 seconds or so)?

For example, say that 2 diodes are lit. then a change to 10 diodes is requested. Instead of instantly lighting the 8 diodes, they would lite up like 3, 4, 5, 6 ,7, 8, 9 and then 10, creating a moving indicator. Each diode could even fade in to make a more pleasant effect.