Three days after I arrived in Cleveland last August, I went to a salsa club. I wasn't expecting to end up dancing salsa that night, but our group somehow wound up there with me in it. I learned a primitive version of the basic front-back step and spent some time on the floor moving like a malfunctioning robot and just generally looking horrible.
Today, with a few more days left for me to stay in this city, I went salsa dancing again. This time I knew roughly what I was getting. In addition to the front step pattern, I learned the side step and a few turns I will have forgotten tomorrow. I spent some time on the floor moving like a robot and looking horrible, but possibly slightly less horrible than the first time.
Every now and then, time does appear to have an underlying cyclical organisation.