The figure starts in a circle:
4 2 6 1 5 3
Bars 1-2: The “first triangle” (dancers #1, #4 and #5) dance clockwise to the next first-triangle position, with all three dancers clashing with each other in the center on the second half of bar #1 as they pass through. Meanwhile, the “second triangle” (dancers #2, #3 and #6) toss counter-clockwise (also on the second half of bar #1) around their triangle.
Bars 3-4: Repeat, with first triangle tossing and second triangle dancing through.
Repeat.
At the end of the figure, the set has now rotated into the following configuration:
5 6 3 4 1 2
All dancers have shifted one position counterclockwise within their own triangle. (Alternatively, you can think of it as the entire set of six having rotated two positions counterclockwise.)