Mathematics is beautiful and a solid understanding of arithmetic is the basis for realizing it. With a pleasant physical representation, this design aims to provide a likable tool for understanding basic mathematical operations.

Changes in v2

As with the previous version cam grooves provide snap positions for the wheels and an inner compartment offers space for miscellaneous.

What changed:

• larger inner diameter of ⌀ 28mm ≈ ⌀ 1.1inch
• inner length increased to 111mm ≈ 4.36inch (suits two times folded A4 or US-Letter paper formats and an IKEA pencil)
• snap action now with three hardness levels
• slightly larger grip area next to the wheels
• printability

A Braille Edition (6-point ICEB) is in progress.

What to print

For multicolor printing and convinience, a 3MF file is provided. There are several modifiers present, deactivate or change them to get your desired outcome.

The axle has multiple indicator styles available via modifiers. Directly painting the knurling pyramids in the slicer also produces beautiful pixelated works of art.

Also the wheels are offered with four different snap actions: light, standard, hard and fixed. → A light detent is recommended for stiffer materials like PLA and/or if an intended user has small hands.

By choosing the type of modifier the wheels are also printable with or without ridges and embossed, flush or debossed symbols.

How to print

The design is optimized for an extrusion width of 0.21mm, 0.42mm and 0.63mm.
It also is divisible without remainder by any of the "standard" layer heights 0.08mm, 0.10mm, 0.16mm, 0.20mm, 0.24mm, and 0.30mm.
For a perfect result the first layer needs to match the other layer heights and needs to adhere well to the built plate. → Keep it slow at least for the first layer.

Any chance to get it a bit different?

Scaling it has partially been tested. A few % usually work well, please report back in case you tried.

The formula to scale this model to your desire is:

• [desired inner diameter in mm] / 28mm = scaling factor
• [desired outer diameter in mm] / 45mm = scaling factor

Blank wheels allow for custom modifications via the text shape tool of the slicer.
Remixes are not allowed, but if you feel like sharing parts with added/changed/customized details or fonts you're welcome to do so as print profile. - If in doubt, please ask beforehand.

What next

There may be improvements and modifications based on feedback given here.

Yes, there is a parametric system behind this design. Several things already have been published and more are planned to come online, your suggestions are welcome.

Maybe, take a look at my other designs ;-)