Bubbles with volumetric- or linear-growth

[FidelioScorpio]

Up to 4 bubbles spawn within the cone of the tree & grow with either constant volumetric increase or constant radius increase (csv-dependant). After a period of growth, the bubbles pop & new ones spawn. When bubbles overlap, the colours combine.

[d-albrecht]

I had to double check with my animation and yes, spheres look that silly on that low-res tree. They are more like patches than spheres, but that's the way the tree is, sadly.

Is the radius when a bubble pops the same for all or some form of random value? Some bubbles pop quicker than I can focus on them. And from time to time there is no bubble at all.

I like the color mixing, despite the fact that bubbles would probably use different color mixing approaches (you know, additive vs subtractive color models), but it really looks cool. The choice of more pastel like colors to begin with makes great mixed colors.

[FidelioScorpio]

With rotating the tree in the sim, you can see the spherical shape in some cases. I would hope that the animation would look better on the physical tree as the visible depth there may assist.
There are always 4 bubbles within the cone of the tree, but they may look like gaps where there are no lights.
The pop point is a maximum radius for the linear-growth bubbles, but is a maximum volume for the volumetric growth bubbles. The maximum value is determined with a random element combined with the growth rate itself so faster growing bubbles last longer.
The colour mixing is simply binary or over any overlapping colours, and the initial colours are constrained random (one of R G or B is >= 0xa0 while the other colours are <=0x80)