Simultaneity models the spacetime diagram for two events occurring at opposite ends of a meter stick.
Twin modes the spacetime diagram of the well known twin paradox. The first twin remains stationary whereas the second twin travels to a distant location and returns.
Lorentz shows how events in Minkowski spacetime transform.
Seeing shows the apparent shape of a moving contracted shape by computing both the Lorentz contraction and the light-travel time.
E&M Fields shows an x-y cross section of electric an magnetic fields for a moving charged particle.