This is a pretty cool video I found at kottke.org, one of my all-time favorite sites where you can find cool things. Basically, it's an automatic hammer powered by water and made from the very stuff of the earth: wood, twine made from viny plants, stone.
The notes for this video indicate the hammer falls at a rate of once about every ten seconds. It might not sound like you can get any useful work out of that, but that belief likely comes from the more traditional, "modern" view of hammering something, which is to beat the hell out of it at a very rapid clip. That does indeed get the work done, but you end up with a sore arm and maybe some recuperation time depending on the job.
Instead, consider this: as long as that little stream of water is running and nothing breaks, this hammer will run continuously, day and night, day after day after week after month. It may not have the precision needed to hang up a picture, but this hammer isn't built for precision. It's built for consistent and relentless force applied over and over and over again. If you need to grind some corn into meal or pulverize some rock into fine powder, this does the trick quite nicely.
My favorite part of the video is when he watches the hammer working for a bit and then walks away from it. It keeps on working while he's away doing something else. I can imagine the odd feeling coming over the first primitive man who built a contraption like this once he realized he could leave the machine alone, working unsupervised, while he tended to another task, like checking the rabbit traps or painting a bison on the wall of a cave or something.
We realize gains in efficiency when we automate certain portions of our lives. Monthly bills, for example, one of my favorite examples. I discussed this one pretty recently. All my monthly bills are as automated as possible so I can do other things (like check the rabbit traps). Amazon has warehouses full of robots which move goods from one end to the other in an orchestrated ballet of logistics... and you'd better believe if there's any one company on this planet squeezing as much efficiency out of its operation as possible, it's Amazon.
Another thing to learn here is that small consistent actions, over time, can make a big difference. One hammer drop every ten seconds over a 24-hour period gives us 8640 hits from the hammer. I'm no expert, but I'd say I personally can hit a hammer about twice a second. I'd have to go at it for an hour and 12 minutes without a break to match this machine... and I'm pretty sure I'd be too tired to continue after much less time than that (and likely would be too sore to attempt it again the next day). The machine could go for another three days or three weeks with no problem, working at only 5% my speed.
Those little things add up. Sometimes when we think they're not making a difference, they really are, and sometimes, they're the only things that are. Little by little, bit by bit... and that unrelenting persistence gets the job done as well as a quick burst of activity. Never give up.