Illustrating Einstein’s Special Relativity: A relativistic diagram that displays in true values the components of a four vector

After having shown that the corresponding components of a four vector transform via the same transformation factors as the space-time coordinates of the same event do, we design a relativistic diagram that displays in true values theirs components. One diagram works for events generated by tardyons whereas a second diagram works for events generated by light signals or photons. We consider both approaching and receding tardyons respectively photons in each case. We also show how the relativistic diagram works for radar and photographic detections of moving profiles.