Colour mixing?

Hi guys. I’m trying to make a simple game which includes mixing colours. My idea is to have multiple coloured circles which you can move around, as you move a red circle over a yellow one, the overlap will be orange. Blue over yellow will be green, as I want it to be standard Red-Blue-Yellow colours you would get when you mix paint, rather than the additive colours you get as RGB on a screen.

I could do it manually with set colour inputs and have a resulting colour, but I want it to be in real time, where I can just have a sliver of a circle overlapping, or have multiple circles all mixing.

I don’t know if this would be easiest to achieve with planes or flattened cylinders of certain colours, with a translucent material similar to glass. Or perhaps if it would be easier with coloured Spotlights or something as they seem to mix pretty well already. The lights would mix additively however, meaning the more colours I add the closer it would get to white, where I need it to go to black the more circles overlap.

If anyone has seen this effect please let me know how best to achieve it. Thanks.