Three examples of Feynman diagrams - invented by American physicist Richard Feynman to help in calculating the electromagnetic interactions of charged subatomic particles. Charged particles are represented by straight lines, photons by wiggly lines. The top diagram could represent a muon at A kicking an electron at B out of an atom by exchanging a photon (wiggly line). The middle diagram shows an electron & positron annihilating at A & producing a photon which rematerialises at B as new forms of matter & antimatter. The bottom diagram represents an electron emitting a photon at A, absorbing a second photon at B, & then reabsorbing the first photon at C.