I've seen the tool I'm looking for on one of those home shows, probably "This Old House" or one of the others.
Let's say you have some stonework and want to make a piece of wood to fit the stonework perfectly. There's a tool to do that but I don't know what it's called. It's made from several metal plates and when you push it against the stonework (or any other uneven surface), the plates take the shape of the uneven surface. Then you can use a pencil to trace the shape on your piece of wood so you will have a perfect fit. I know you can use a compass but this tool I'm trying to find would work better.
Anyone know what I'm talking about? If so, what's it called?