These diagrams were developed by the American physicist Richard Feynman as a way of showing the interaction between two sub-nuclear particles. They represent what is happening between the two particles during an interaction.
Each point where lines come together is called a vortex and at each vortex charge, baryon number and lepton number must be conserved.
The full straight lines represent particle directions and the wavy or dotted lines represent the path of 'exchange or virtual particles' such as photons or pions during the interaction.
The arrow of time is shown at the right.
