Small circuits - Ideas needed for my Fidget Cube!

Hi all!
I'm currently working on an element14 presents project, to make a electronics/engineers fidget cube. What do you think, good idea?

My original aim was to make a 1" cube with small circuits on each side, but fairly quickly I realised this was going to be tight on space, I have now upped the size to 50mm cube (approx 2").

My design spec is as follows:

• One side is a power supply, has a LiPo battery input and outputs 5v to 5 Molex PicoBlade connectors.
  • Pin1: +5V
  • Pin2: GND
• Each side is completely stand-alone, has no dependency on any other side, other than the power connector.
  • All processing must be done on that side's PCB
• The visible area of each side is 40mmx40mm
• The PCB is 44mm by 40mm (This has a 2mm edge on 2 sides to slot into a 3D printed framework which will hold all the PCBs in to a cube shape.

I currently have the Power supply PCB designed, this also includes a fidget element of a push button which will turn 8 LEDs on and off

Front and Back:

The next side I have designed is a logic gates and Binary counter board.
The top half has inputs A and B, and surrounding them the output of the following gates, based on input A and B, OR, XOR, NOR, XNOR, AND & NAND.

The lower half has a 6 bit binary counter, with a button to increase and decrease the counter.

Front and Back:

I am planning on a "sketch side" which will consist of an LCD or OLED display and a joystick which will allow you to draw lines on the screen (Think Etch-a-Sketch).

This is currently proving hard to fit into the space and design requirements, but I think I've got a solution, but I haven't modelled this yet, so you might just have to trust me on this one (and I'm desperately hoping I've done the PCB correctly for it to all work like I've planned!)

The framework to hold these into a cube will be 3D printed, and currently looks like this:

The red is the top half and the blue shows the bottom, these will slide over the PCBs due to a groove on the 4 outside faces. The top and the bottom will need some hotmelt glue or other fixing method designed into the 3D print to hold them in place. Potentially an internal framework which will push against the back of the PCB and also securely hold the LiPo battery pack.

So what do you think of this idea?
Have you got any suggestions for the sides I've already come up with? Improvements, or criticism welcome!

I still need 3 sides, if you have an idea for a side then please let me know and I can design it for the cube. Or if you would like to try designing a side I'd love to see your design.

With the sides being independent and fitting the design criteria, I'm thinking they could be interchangeable and swapped in and out.
We could invent our own swapping system, if someone designed a side and makes a few and swaps them with other people who've made their own, we could all make our own unique fidget cubes!

Please feel free to tell me if I'm getting carried away now...!