The important part is "setColour(colour.x, colour.y, colour.z, 1)."
From what I can assume, colour.x is for the "red" value, colour.y is green, and colour.z is blue. Go ahead and change all of these to a value within "1" and "0." If you want to make everybody, say, orange, you make it (1, 0.5, 0, 1).
If everything else but the fourth value is "0," then if the fourth value is "0" cells will be black, and if "1" then they'll be white. Don't think it does anything if any of the other three are anything other than "0."
Apparently, "colour.x" and the rest are supposed to be imported from each species' individual data. No idea where to find that (stumbled on this because I was looking for the species names and got sidetracked), but whatever. The point is, you've set everybody's membranes to the same script, so they'll be uniform.
One thing to note is that it only seems to work if you start the Microbe Stage without editing, since editing it makes your cell different from the norm or something.
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