It can be done in two groups of lines. Do them in place. Groups start from opposite ends of the floor, facing each other. They are in lines both across and front to back. One side is offset so they can pass down between the dancers in the other group.
Dancers proceed toward each other.
When the two groups meet, they will go through each other's lines. On each shuffle pattern after the Lindys, you will pass one row of dancers. On each full dance pattern you will pass two rows. Then you move forward another 2 rows on the forward shuffles When the groups have gone completely through, they continue to the end of the floor. If their is still music left the groups do an half turn on the last 3 steps of the pattern and go towards each other again.