Planar linkages As part of a doctoral schooling program, Mickaël Kourganoff, Thomas Letendre and I designed a workshop for the travelling exhibition MathALyon, which Pierre Gallais then built. It is about planar linkages, and more specifically on the adder and on the Peaucellier inversor. Here are instructions intended for pupils, directions for use intended for supervisors (written by Mickaël) and proofs (written by Thomas).