Mathematical object for illustrating angles of repose (sandpile) on display at Matemateca (IME/USP)
Object made by Estes Objethos Atelier, video by <a href="//commons.wikimedia.org/wiki/User:Rodrigo.Argenton" title="User:Rodrigo.Argenton">Rodrigo Tetsuo Argenton</a>
CC BY-SA 4.0
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>