I was contracted by my sister Sara, in return for her gracious hospitality and her husband's air compressor, to make a birdbath of limestone. They had recently redone their entryway with some very cool flagstones and boxwoods. I used the set of air hammer and chisels I obtained several years ago for my nephew Isaac (with some oil and lots of shaking and tapping), and my brother-in-law Tim provided a diamond-bladed electric saw (lots of resetting the 110v breaker). I think you should be able to make out and distinguish the marks from air hammer with different chisels, from the saw marks. My only hope was that some birds would fit. After two hours of chiseling and sawing, maybe a chickadee. After four hours a small robin or cardinal. After six hours, it was getting dark and rainy. A bath for a crow! Maybe it's not done and I'll work on it some more next summer. I decided to clean up and get some dinner! As I cleaned up, I noticed a large (150) flock of geese heading south. Please know that if you contact the Bloomington IN Area Arts Council at www.artlives.org, you can learn to carve limestone this summer. I did it, survived and was empowered to carve this stuff!