Take a close look and see what is hidden in foot 39C or maybe you have a foot that has this surprise.
https://www.bernina.com/en-CA/Accessories-CA/Presser-Feet/Decorative-sewing/Embroidery-foot-with-clear-sole-39C
https://www.bernina.com/en-CA/Machines-CA/Quilting-Machines
The quilt in the background is in my book https://sewveryeasy.podia.com/hand-signed-copy-of-quilt-favorites-book and here is the video https://youtu.be/z_78C5bpdw0