There is an example in the corner of the picture of the dancer leaping over a ty...

Stratoscope on May 24, 2020 | parent | context | favorite | on: A 1973 IBM Selectric typeball recorded dancers' bo...

There is an example in the corner of the picture of the dancer leaping over a typeball. But yeah, it is just a small example and there is no explanation of what the symbols mean.