From a 3/4 tag (or 1/4 tag, or whatever), the centers 2/3 Linear Cycle
to become #1 and #2 of a column. The ends Reverse Single Rotate and
then Split Counter Rotate to become #3 and #4.
\sxvLBLs{g4n,b3s,g1n,b4s}
\syhlines{b4e,g2e,g3e,b1e}
before Gravitate
after
If the center wave is left-handed, a collision occurs, resulting in "clumps".