Plus Plus Brick System - Custom Shapes

My 4yo kid loves the Danish Plus Plus brick construction toys (https://www.plus-plus.com) even more than LEGO. It's a really simple design that are easy to assemble and manipulate for small hands. It's more forgiving and easier to disassemble than LEGO.

However, because Plus Plus bricks are limited to only ONE shape, I find it somewhat limiting in terms of creative options. So, I decided to model some new variations on the Plus Plus brick and print them out in PP, so they'd be compatible with the original bricks (made of PE). I stuck w/ a design paradigm of simple 2D profiles, based on multiples of the basic 4mm square interlocking cube, to keep the shapes simple and true to the spirit of the original parts. Of course, we can expand out into 3D and I may do so for the next iterations.

I'd love to see how you use these parts in concert with the original Plus Plus bricks. Please also share if you design new shape variants! Let's share the fun :-)