OK, pictured below is my $8.00 garage sale find of the day. It's got to be 50-80 years old if it's a day, and it's made out of thin strap iron bolted together with round-headed stove bolts and square nuts. It's rather rickety and I don't imagine it will be robust
enough for anything except possibly weeding in already-tilled soil or perhaps decompacting lightly-compacted soils; it's certainly not robust enough to break sod.
Even so, I think it's rather nifty. There doesn't seem to be a lot of information on the web about hand plow history or uses, but then again, perhaps I don't know where to look.