I always enjoyed the explanation from the N game: https://www.metanetsoftware.com/technique/tutorialA.html https://www.metanetsoftware.com/technique/tutorialA.h

I always enjoyed the explanation from the N game: https://www.metanetsoftware.com/technique/tutorialA.html https://www.metanetsoftware.com/technique/tutorialA.html Back when flash was everywhere.