Canon. Each 40 bars a new couple starts, and dances 80 bars.  Requires 5 x 40 music.

The instructions for bars 13-16 in Tweeddale Book 4 just have "turn both hands half way round" in 4 bars (for finish back to back). In the <<https://youtu.be/jsj9qsrbSfg|video>> of a class taught by the deviser they appear to set advancing then half turn in 2 bars. The diagram reflects the instructions whereas the cribs follow the video.