This is a picture of the bottom of a "Guy Derrick." Think of it as a steel mast about 100 feet high with 2 inch wire cables streached out in all directions. There were perhaps 10 of these cables that held the mast vertical. A big wheel at the bottom, had attached to it, a boom that was also about 100 feet long. A cable ran through a series of pulleys to raise and lower the boom for position within the quarry below. A third cable was the actual hoist line. The operator could swing the boom in a 360 degree circle, raise and lower the boom as long as it was under the guy cables that held everything vertical, and he could hoist a block of granite out of the quarry hole. This device could pick up a 100 ton block. Some were rated even higher. See the hoist house in the next picture.