Spacetime Calculator
This Swing application allows users to plot events in two-dimensional spacetime. It demonstrates how events transform between reference frames, and how concepts such as simultaneity or two events being in the same place are frame-dependent. Additionally, it allows users to calculate how far two events are from each other in spacetime; whether they are timelike, spacelike, or null separated; and whether they appear to be simultaneous or in the same place in a given frame.