These are toy model kits familiar to tinker toys, kinex, and legos. Most of the time*, if you hear anyone over the age of 13 and not the parent of a 10-year-old referring to them, it's about the penis and its many functions.

*I was proven wrong about this when a 16-year-old friend of mine told me a story about when he moved here last month and the couch legs turned up in his erector set's box. I'm still letting that one sink into my brain.