Depending on which side of bed you got out of this morning, this is either a grid square or a 4-face-4 double-progression contra. Extra fun comes from progressing alternately down the hall and across the hall, so everyone gets thoroughly mixed around.

To get the spacing right, set it up as a grid square. Have each square join hands in a ring so everyone can see to line up the squares in rows and columns. Make sure they're straight, with no gaps. Then have everyone move a bit to their left to form lines of four facing four up and down the hall.

You need 9 squares minimum, the more the better. If any row has only one square, move a square from a different row—for example, 3+3+2+2 is better than 3+3+3+1.

Form a square in A1 after swinging your corner, who is next to you if you're in the middle of the line and across from you if you're at the end of the line.

Head couples and side couples alternate leading the C1. No one is with their partner at that point, but in successive changes heads remain heads and sides remain sides (until hitting an edge and swapping roles). After the left-hand star all face original partners, and you're lined up for a hey with the people in your original line of four.

End the D1 swing in lines of four, facing the couple you did the hey with. The lines form alternately at the sides and at the heads in successive changes. If dancers face their hey mates everything works out, but of course it's best to keep it straight in your own head and call e.g. "Face across the hall, lines go forward and back".

To help with the D2 progression during the walk-through, look past the line facing you to see another line of four and then look past that line to see a third line of four. You'll be dancing with that third line next—pass through the first and second lines to meet them. If there's no second line, do a California twirl and face back into the set.

I wrote this dance after a trip to Lowell Massachusetts to see the Industrial Revolution factory museums. The alternating progressions reminded me of all the warp and weft in those amazing waterpowered looms.