This is a off-topic but a funny story about the "Puffer" Machine.

I was doing a dog & pony show for the Premier of China on the behalf of GE. Basically they wanted to get the Chinese to buy more locomotives, imaging equipment, and, yes...puffer machines.

So they have actual equipment for this show, including a puffer machine, just in case the Premier wants to see something in action.

About 2 hours before he is set to arrive, we're all told to leave the area, as the (I assume) Diplomatic Security Service is doing a bomb sweep (the show was in the US).

Next thing I know, all these agents are running around like Oswald is in the building or something.

Seems that they use a small amount of explosive material to calibrate the puffer machines, and the dogs got a hit off it. Took about 30 minutes for them to figure out what was going on.