The other day, I thought I'd design a 3D-printed box. This wouldn't be just any old box, but the question-mark block from Super Mario Brothers. I started to break down what would be involved in the design. I would have to come up with the base box template, then virtually punch out a grid of dots representing the correct pixels. But, I thought, if I was going to do the work to calculate a grid of pixels on the box faces, I really could just put any pattern on the side. And if I could put any pattern, I might as well turn it into a template. And if it was a template, then other people could come up with some pretty cool designs that I never even thought of.
The following box-builder runs entirely in your web browser. All you need to do is check and uncheck the grid of boxes at the left. This alters the OpenSCAD code at the right. When you have reached the design you like, select and copy the corresponding code at the right. Finally, paste that code into OpenSCAD and generate your 3D STL file to load into your 3D printer.
(Note that, for me at least — on the MakerBot Cupcake with MK6 Stepstruder — the resolution of the final STL file is slightly higher than that of the printer. Specifically, I get solid horizontal grid lines between rows, but no vertical grid lines between columns. In my opinion, then ends up looking a little nicer.)