@DrYohanJohn
This reminds me of a loop in Feynman diagrams, which can be interpreted as (if x-axis is time) a photon decaying into an electron-positron pair that is annihilated immediately after to create another photon. Or if y-axis is time, a virtual electron-positron pair created from nothing and quickly destroying each other.
Pizza traveling forwards in time would be the electron, and when it is traveling backwards it would represent the positron.

*Read with a 1 kg grain of salt, I'm not a physicist* haha