Fraction Bars "Wiener Bruchrechentafel"

**Educational Tool for teaching Fractions to the Blind.**

* Original design dates back to 1910 or earlier.
* Idea to recreate the design for 3D-printing by Golan Levin.
* Discovery of original design and CAD model by Martin Schneider.

Source: *Archive.org*

Alexander Mell, [ Der Blindenunterricht. Vorträge über Wesen, Methode und Ziel des Unterrichtes in der Blindenschule](https://archive.org/stream/derblindenunterr00alex#page/112/mode/1up), 1910