Knitting and communication in public transport

today i was on the train. a lady who looked like a librarian was sitting in the seat beside the one directly in front of me. she took out her knitting needles, and started knitting on a thing that looked like a legwarmer for an elephant. but she didn't look at what she was doing, instead she looked out the window. a few stops later, a man who she obviously knew got on. he had long black hair that hadn't been washed for a month, and a black beard. he sat across from her (next to me). she smiled at him, and he smiled back. then she went back to her knitting. they continued to look at each other, but didn't say a word. after a while, they both suddenly burst out laughing. i tried not to stare. then i noticed that her knitting was a bit odd- every stitch seemed to be different. most people would just think that it's just some complicated pattern. but to me it seemed more that this was their way of communicating. a while later, they laughed again. then, she got off. and not with this man, but with some other guy, sitting at the other side of the car. they walked off, talking in loud voices. if i ever learn a foreign language, i want to learn to knit.