Upcoming 2D illustration/animation apps, in which the lines & shapes you draw are connected both in space and time, allowing for faster editing and inbetweening
Learn how to represent Möbius strips and 2D vector graphics shapes sharing a common edge in a May 2019 IEEE CG&A Dissertation Impact article by @dalboris. See video at youtu.be/ZtxLMc9_yQ0.