It is better, but not essential, to have an even number of couples
When reaching the end oif the set in B1 you should complete the turn with an imaginery couple above or below.
When standing out, change sides immediately, and do the back-to-back with the approaching couple, but do not join in abything else. The other couple will use you as 'posts'.
B2 can be thought of as 'interlocking heys' with the 1s doing a morris hey and the 2s doing a grimstock hey.
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