Various types of 2D graphics can be considered as follows:
Flash: Flash is not dead yet and is still around although it is being used less today. Nevertheless until Flash has finally been retired, it is worth keeping some expertise in it. An animation of a 7 segment telescope is given in this link.
Applets: Like Flash, Java Applets are used less today, and as with Flash, as long as they are still being used, it is worth keeping some expertise. A graphics of Jupiter with its 4 Galilean moons is shown, with the moons in their positions based on the time and date.