Print your own dichroic filament (multi color). When using the printed octagonal filament you need to set flow to 1.12 (112%) to compensate for the shape else you will get under extrusion.
This also allows to create blends - therefor you need to print the filament with an already printed filament to mix the colors more. You can create a shade or with translucent filament you can make a cloudy diffusor (90% clear 10% white)