Sculpted Gear Shop

I found the shop where Cogsworth Linden purchased the gears. He mentioned that they were 500 L$, but it turns out they are actually 4,000 L$! I had to think hard about it. It’s about 15 US$ that I would be spending. After thinking hard about it, I purchased the gears, a wooden bridge made of four prims for 499 L$, 128 building shapes for 1200 L$ and a path tiles sculpted for 500 L$. In all, about 23 US$. Can we say impulse buy? What I want to know is how do they do hard edges with sculpts? And how do they make one sculpt look like separate multiple objects?