Adriane Kaïchouh, Mickaël Kourganoff and myself designed a workshop for the Maison des Mathématiques et de l'Informatique (House of Mathematics and Computer Sciences) and MathàLyon. The latter is a travelling exhibition inspired by Experiencing Mathematics. It aims to make high school students (and others) experience mathematics in a ludic way.
This workshop is about planar linkages. The students can use some elementary blocks to build either an adder, which adds two vector in the plane, or a Peaucellier-Lipkin inversor, which realises an inversion with respect to a circle. It was made by artist Pierre Galais.
One can transform a circular motion into a linear one and vice versa using a Peaucellier-Lipkin inversor. You can see one in action here for example.
Here are some documents related to these planar linkages (in french). Instructions intended for the students (.pdf,.tex) written by Adriane, instructions for supervisors (.pdf,.tex) written by Mickaël, and some proofs (.pdf,.tex) hopefully understandable by high school students.
Finally, here are some Geogebra simulations of planar linkages.