So I used a ton of brushes with only one color spectrum. (Cyan-Teal), dragging it around randomly.

and then I blended it all together. So The idea for the challenge in which I came up with is to take one spectrum, and scribble with a ton of different brushes, blend it together, and the next person has to use that base color and pick a new spectrum (any random color besides the curent base) and do the same.

Let's see if anyone wants to join in (1st person starts with the resulting blend, 2nd person starts with 1st's blend, etc)

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(example of the continuation)

((For the final color, everyone must make a drawing themed around that spectrum, and that will be another challenge with reward.))