Interesting concepts. However I want to use the logo on a white background and of the three, #136 would seem to be the only one that works -- and I think the pen tip gets lost at the top (or is your intention to outline these concepts with a thin black line so they pop a little more?
Very nice concepts. The only feedback I have though is that in some of the rainbows, the colors aren't blending -- for example in 144 it goes from light green to dark green and it's a dsudden effect instead of a gradual effect. Same thing with #141 -- you can see the different bands of gold rather than a msooth transitional gradient.