For comparison: factorial(3) visualized in two different notations.
John Tromp's Lambda Diagrams (via 2swap): https://www.youtube.com/watch?v=RcVA8Nj6HEo&t=1346s
Bubble Notation: https://www.youtube.com/watch?v=aRgu8S3Pnb8
2swap has some incredible videos
Here's another from a long time ago: https://dkeenan.com/Lambda/