Okay, Arlo actually moved most of it. But I moved some of the smaller pieces, and I did pick it out, pay for it, and tell him where it should go. I know, that's much less impressive.
I could, I think, have lifted and laid all of these. Just barely. But then I'd have to lie down for a week to let my back recover.
These aren't installed yet, btw. Tomorrow (or the next day, if tomorrow is too rainy), he'll use a spade to draw the outline of each of these, move them aside, dig out their depth, lay some leveling sand, and then put them back in, so they're just protruding a bit above the surface of the soil.