I have begun making things in pottery and paper mache in groups of three, with related function and variations on a design theme. The idea began when I was thinking of ways to reduce the percentage of shipping costs for online sales (triple the sales price, no increase in shipping costs for three paper mache items that fit in the same box). Now, I find it interesting to think of what three things can be grouped together and how the designs can vary.
Tea light holders were an easy start, as I always think you should light three at a time. You can see the idea of design variation here.