That's what made me think it was home made. The chips were random, they didn't look shaped at all. The closest thing it reminds me of would be a kid putting rocks in interesting designs on the beach.
That has to be a very early MOP from Singer.
Funny how things go from "It looks a little unrefined" to "Great Find! it's some of their early work!"
Kind of like an artist's work. It all depends on who did it.
Rodney