This has 4 parts. From facing couples, Sweep <N/4> clockwise,
Veer Left, Tag the Line, Leads Roll Right to a Wave.
The sweep is always clockwise (unless the caller said "Reverse"
or "Mirror".) If that isn't the same direction that a plain
Sweep 1/4 would have obtained, the awkwardness is the caller's fault.
\phBB{g2s,b1n,b2s,g1n}
\phBB{b1e,g1e,g2w,b2w}
\pvfour{b1e,g1e,g2w,b2w}
before Clean Sweep 1/4
sweep
veer
\pvfour{g2n,b2n,b1s,g1s}
\phBB{b2n,g1n,g2s,b1s}
tag
finished
If the caller says "Reverse" or "Mirror", all parts are
reversed: Sweep counterclockwise, Veer Right, Left Tag the Line,
leads Roll Left.