First phrase:
The people in lines 1 and 3 begin with the top rhythm of phrase "A,"
traveling in a half circle or oval. Meanwhile, the people in line 2
begin with the lower rhythm of phrase "A," centered between lines 1 and
3.
Second phrase:
Lines 1 and 3 turn around to perform the top rhythm of phrase "B,"
essentially returning along the same path. Those in line 2 don't turn
when the others do, but continue on to complete the circle or oval,
performing the lower rhythm of phrase "B."
Third phrase:
The three lines meet up again to begin phrase "C," with line 2 facing
toward a counter-clockwise path, and lines 1 and 3 facing their
clockwise path. They pass each other, as lines 1 and 3 perform the top
rhythm of "C" as if to begin another half circle, and line 2 performs
the lower rhythm of "C" in the opposite direction.
Fourth phrase:
Lines 1 and 3 turn around again to step the top rhythm of "D," traveling
with as much space as possible, in a nearly complete circle that catches
them up to the people in line 2. Meanwhile, line 2 continues in their
same counter-clockwise direction, performing the lower rhythm of "D" to
complete another half circle or oval.
Note that there's a great deal of difference in the amount of space the lines need to travel in the fourth phrase. It looks as though all groups should conserve space in the third phrase so they don't get too far apart, and then in the fourth phrase, line 2 should continue to travel with as little space as possible while lines 1 and 3 will need to cover a lot of ground in order to catch up. Looking at the respective rhythms they're stepping, this looks like a real challenge! (One way to conserve space, for example in line 2's last "D" pattern, is to take some of the steps backwards, sideways, or turning.)