No information can be conveyed by the wavefront and so nothing is actually moving than the speed of light. What you diagrammed is called the Lighthouse Paradox:

No information can be conveyed by the wavefront and so nothing is actually moving than the speed of light. What you diagrammed is called the Lighthouse Paradox: * https://en.wikipedia.org/wiki/Lighthouse_paradox https://en.wikipedia.org/wiki/Lighthouse_paradox There are similar things that appear to exceed the speed of light: * https://en.wikipedia.org/wiki/Faster-than-light https://en.wikipedia.org/wiki/Faster-than-light See "group" and "phase" velocities for similar things to the lighthouse.