I knew an engineer who used to work for a US company that made nuclear reactors. He had said that they sold a single reactor to someone in China, and only one.

I knew an engineer who used to work for a US company that made nuclear reactors. He had said that they sold a single reactor to someone in China, and only one. Several years later they found that they had made many identical copies of that model reactor, down to the size of the bolts.