# Clarification regarding animation on path integrals

It's a pretty animation. Sadly the wiki page only says the following on the animation:

The diagram shows the contribution of a set of paths for the path integral of a free particle.

Can anybody tell me what this animation shows exactly? I assume it has something to do with the phase factor, but I can't seem to figure out what exactly.

• Try googling Cornu spiral – mmesser314 Feb 28 at 3:24

Here is an example image, shown in Feynman’s highly readable QED book. It is talking about a light emitted at $$S$$ and detected at $$P$$. $$A-M$$ is a mirror. Each path has an associated time (taken to cover the path) with it which tells us what the phase is. So we pick a fight pointing arrow to represent our reference phase and calculate the relative phases accordingly.