Sweet Miscellany

I had never heard of the Cornwells before finding this gem of a film on archive.org, but I am glad I know about their work now. The film shown below is from 1977, and does a good job of explaining congruent triangles. It is a bit slow at first, but the last 90 seconds really are beautiful. It is like Leger or Seurat had an opportunity to make a film for your high school geometry class.