Hal, thanks, I'll look at those
Roger, yes, that's the trick, put them at an angle. There was some article that mentioned that, maybe yours? In rocky soil it's sometimes hard to get at the right angle. You have to search around for a path into the ground that avoids rocks.
Chad, that would help to have the hook bend around the other direction first, then wrap around the other. That's fixing the problem I've encountered. I've kind of done that to my stakes. But, then it's more springy when you pound it in and more likely to start bending.