I once interviewed with Boeing research and gave them the spiel about my PhD work on network protocols. They started asking me about Petri nets. I know nothing

I once interviewed with Boeing research and gave them the spiel about my PhD work on network protocols. They started asking me about Petri nets. I know nothing about Petri nets other than that they're another approach to distributed systems. I'm fairly sure I left them convinced I didn't understand my own research.