Harmonograph on display at Matemateca IME-USP
Exhibit made by Estes Objethos Atelier, photo by <a href="//commons.wikimedia.org/wiki/User:Rodrigo.Argenton" title="User:Rodrigo.Argenton">Rodrigo Tetsuo Argenton</a>
Matemateca (IME/USP), provided via digitalization project by the user: <a href="//commons.wikimedia.org/wiki/User:Rodrigo.Argenton" title="User:Rodrigo.Argenton">Rodrigo Tetsuo Argenton</a>