I just purchased this 1913, model 15, serial number G3390154. based one my 3 days plus of research this was one of Isaac's major step forward's in machine design, but he pasted before he got to see this machine in production. I'm still in the learning process of my passion for the Singer sewing machine, and have learned that some machines were givin "NickNames" Tiffany,,RedEye,Sphinx..Is there a Nickname for this disign..I refer to it as "Mosaic" based on the tile like gold leaf design to make up the decal's trimming the machine..Also threw many hours of search..I have only found one unit from that year/model, for sale and it was for parts and in the poorest condition I've ever seen. It is in a beautiful cabinet, with a knee pedal/electric, which Im guessing threw reading was one of the options for this machine besides a treadle. Does anyone have any input on this unit? that can help me be more informed on this beatuiful machine?