When I was a kid once I asked my father is it possible to make colour TV using red green and blue leds. After few years its in market. In the place i stay it hard to get rgb led as such so i was using separate leds to make combination of colours. And arduino has only 6 PWM and I wanted to make rainbow while stubmiling in google I found out one guy has done it. So i started to make rgb modules. Its creates PWM at higher frequency and Multiplexes it common cathode. Paper cylinder made a vibrant effect. This project uses multiplexing so brightness will be less.