Uh-oh… here comes the Machine. What's that, you say? You don't know what the Machine is? It's Count Rugen's special device for creating as much pain as possible in the human body. So when you think about the Machine, you should also think about Count Rugen and his sadistic fascination with pain. The Machine has:
Little soft rimmed cups of various sizes and a wheel, most likely, and another object that could turn out to be either a lever or a stick; it was hard to tell. (6.240)
Yeah, so the Machine actually looks pretty stupid. In fact, "The Machine looked so silly Westley was tempted to giggle" (6.258). But Westley isn't laughing for long once he's actually hooked up to the thing. This Machine is actually the thing that ends up killing him. Oops.
In short, there are bad people and good people in this book. And since Count Rugen causes people pain because he simply likes it, he's one of the baddest dudes around. The Machine makes this explicitly clear. After all, it didn't build itself; Count Rugen spent time on this, crafting the ultimate torture device for his own joy and curiosity.
The Machine represents something else, though, too, and that's Prince Humperdinck's cowardice. Instead of fighting Westley himself, he leaves him to the Machine and it's terrible machinations. For the full impact of this, be sure to read up on the Zoo of Death elsewhere in this section.