It seems that the din of Sandal HaMsumar is if the sandal is nailed from the top, since Rav Sheshes says it's permitted if the bottom has nails to prevent it from wearing out, and noone argues. Also, from the patterns that are permitted, it would seem that the masmerim are on the top.
But, this doesn't make sense with the incident of the footprint at the entrance to the cave. So I am confused as to what is really meant.
Tuvya Marcus, Jerusalem, Israel
The way I understood it, Reb Tuvya, the nails are pounded in from the top of the shoe; perhaps they attach the leather upper to the shoe. Their heads are exposed, hence the concept of nails that are "l'Noy", for beauty. (Nails on the bottom of a shoe do not add to its beauty.) The points of the nails protrude at the bottom of the shoe, where they can clank on the rocks and be seen in shoeprints.
The Gemaras that you cited do not show otherwise. Rav Sheshes meant that just as too few nails are permitted (i.e. up to 5,7,13,22 or 24), too many nails are permitted (i.e. if they cover the entire sole) - since that shows that their purpose is only to protect the sole from wearing out.
I'm not sure what proof you found from the patterns; have a look at our picture of a Sandal ha'Mesumar at www.dafyomi.co.il/shabbos/graph1.htm.
Regards, Mordecai Kornfeld
In this picture, it seems to me that the nails would be obscured by the person's foot when the sandal is worn, so how could they be "L'Noy"?
Meir Eliezer Bergman, Manchester UK
The heads can be seen on the upper side of the sole. I presume that the nails were banged into shoe at the edge of the sole, attaching the sides of the leather upper to the sole on bottom. The nails were not covered by the upper since they were at the side, not in the part that the foot slides into, so they were visible.
You are correct that this is not the way it appears in our picture; it should be corrected.
Best regards, Mordecai