- Affine transform : https://www.youtube.com/watch?v=cQYbp4IGkgQ (Hacking with Swift YouTube)
- CALayer Strokend: https://www.hackingwithswift.com/example-code/calayer/how-to-make-a-shape-draw-itself-using-strokeend
- Substrings in Swift: https://stackoverflow.com/a/39677331