Caption: The standard image of a coordinate system for explaining both the Galilean transformations of classical physics and the Lorentz transformations of special relativity.
Features:
At time zero, the 2 coordinate systems exactly overlapped.
For example, the Galilean transformation for a velocity in the x direction from the unprimed to the primed coordinate system is
v_x' = v_x - V and the inverse is v_x = v_x' + Vwhich is what you would expect.
This does NOT happen with the Galilean transformations---which were the transformations that were thought to be exactly correct (by most people) before the discovery of special relativity in 1905 by Albert Einstein (1879--1955).