In Decker 1.52 I overhauled the brushes.deck example to make it a full interactive tutorial: All About Brushes!

I hope that this sheds some light on a feature that has remained a bit obscure and under-utilized so far. I'd love to hear your thoughts on this new tutorial. Do you find it helpful? Is anything unclear, or is it missing information you'd like to see?

As a bonus, here's an extra little Lil fragment that describes a brush which cycles through a configurable "rainbow" palette. Give it a spin:

i:image["%%IMG0AAsADQ+AP8B/wP/g/+D/4P/g/+D/4P/g/8B/gD4A"]
#c:47,44,32,37
c:39,36,32,36
n:0
brush[on rainbow do
 n:(5*count c)%n+1
 i.copy[].map[1 dict c[n/5]]
end]

What brushes can you folks dream up?