This is a simple utility for finding Feynman diagrams corresponding to a physical process.
Enter the list of incoming and outgoing particles, and specify how many internal vertices you want. Then click 'Go!'.
If a diagram is unclear, try dragging the vertices around with the mouse.
Only QED is supported. $-1=e^-,~1=e^+,~0=\gamma$. Separate particles with commas.