Originally Posted by BarbaraSue

Charlee knows better than I. I believe the first one in the second photo is a zigzagger. Another of my machines has that on a foot. The fabric goes between the "S" loops, and as you sew it zigzags the FABRIC with your straight stitches. another site showed how it worked on a treadle machine, and the demonstrator said that she would never use it for any length of time as keeping the fabric correctly oriented was very difficult to do.