DH has gotten the hang of this garage thing now, and while I was away quilting with Mary, he was installing a great big compressor in our garage. Why? you ask. Because he has tools that are run by compressed air rather than electricity. They don't need batteries. They don't require wires running to outlets. But they do need heavy duty air hoses. That air has to come from somewhere, and this big green cylinder is what will supply that for him.
When a compressor runs, the rotating assembly of the cylinders on top of the compressor motor create some vibration. This may cause the compressor to move unless it is anchored or has some method of dispersing the vibrations. DH built these gravel filled pads to do just that. Isn't that clever?!