A self-aligning Boggle board

Earlier this year Charlie challenged me to make a Boggle board that always leaves the letters upright, and this week I have succeeded.

I have a video demo here:

And you can get the files at https://www.printables.com/model/625901-self-aligning-boggle if you want to print one yourself.

I initially experimented with a system of gears that would rotate the cubes into place, but gave up because I couldn't convince myself that it was going to work. But last week I stumbled across the idea of solving the problem purely using the shape of the cube, with no active mechanism involved.

The only "active" part is that you have to shake it to get the cubes to line up, but you already have to shake it to shuffle the cubes anyway, so I think this is quite an elegant solution.

The cubes are made out of shapes that are like a circle on three corners but a square on the fourth:

With a ramp around the edge of the pockets, to encourage the cubes to fall into place under gravity:

They don't fall into the pockets perfectly every time, but the mesh lid makes it easy to tell if there are any mis-aligned cubes, and you can jiggle it a bit until they fall into place.

I have put steel rods into the centres of the cubes to add weight. This helps a lot with making them fall into place instead of sitting on the edges of the hole, and it also prevents them from bouncing out of their pockets again when jiggling.

I need a better way to paint letters on to parts like these.

Normally I try to make areas that I need to colour stick out, and then it is easy to drag a Sharpie over the high spots, but in this case if the letters stuck out they would interfere with the shape of the cube, so they need to be set in instead. Painting them is very tricky because the paint likes to run in the layer lines, and it is easy to accidentally bump the brush against the edges of the hole. If you have a multi-material machine you could do a much better job.

The mesh lid is very satisfying, it is made out of 20% gyroid infill, with a "modifier cube" in PrusaSlicer to set 0 top layers and 0 bottom layers. It feels surprisingly springy.

I have submitted the design for my self-aligning Boggle board to Spark Hasbro (Hasbro are the makers of the official Boggle game). Spark Hasbro seems to be designed for kids to send crayon drawings of their toy ideas, but maybe they will find self-aligning Boggle interesting.