Spirograph

A cycloid is a curve drawn by a point rolling a circle over another circle. The branches of cyclodida then resemble a flower or a snowflake. The mechanical aid for creating a cyclodide is called a spirograph. These are two gears that roll off each other and a cycloid is drawn with a pencil in the hole.

More about it available on: https://www.maclab.sk/clanky/en-spirograph.php