Factorials and the Gamma Function (Geogebra and Python builds) - for Stand Up Maths - Matt Parker

From a channel Lumen includes in full: SparksMaths (Ben Sparks) records GeoGebra build sessions that model maths ideas (curves of pursuit, caustics, polyhedron nets), many accompanying his Numberphile videos.

A 31-minute video from SparksMaths's catalogue; the title names its topic.

Video by SparksMaths, played through YouTube's embedded player.