I like an easier flow to my coloring books than I've seen in the stores; designs that are interesting and different, but easy to complete in a short amount of time. But then...what do you do with it??
What if it were a card? That you could "Color and send... or give as a gift to an artistic friend!" Perfect size, do-able as a short project, and useful: Fun to create, fun to send, fun to receive...THAT'S IT!
How about this: sit and color, with a cup of coffee and then write a note. Mostly~JUST RELAX! It's good for your brain!