An extruder is a tool (mine was made for polymer clay) that pushes out a line of clay in a variety of shapes. I haven't used mine that much and sometimes I wonder why. It is such a handy little tool.
This is a Makin Extruder, which can be bought in any craft store. It comes with a large variety of (for lack of a better word) templates. These templates are placed in one end, the clay goes in the other end and then the handle is turned..... pushing the clay out through the template. This creates a line of clay in the shape of the hole in the center of the template. The templates come in a variety of shapes, triangles, squares, rectangles and circles to name a few.
For the "Screw" pendant I used the square template for the outside edges. I needed something to create the well that would hold the resin. Since the size of the square extrusion was rather large, I cut it into fourths after extruding it. The inside divisions were rolled by hand using a flat sheet of Plexiglas to make them more even.
Another great feature of the extruder is it's ability to make hollow pieces. (It did take me quite a little while to figure out how to use it. Unfortunately it's been quite awhile ago, so I'm sure it will take me that long again.) These templates push out something equivalent to a piece of "macaroni." (Tried covering a piece of spiral macaroni once with metal clay paste........ it didn't work.)
This piece took me a long time to make as I wasn't sure how I wanted to finish it. I made the focal piece in a class and obviously my idea changed along the way. I didn't finish it the way I thought I would. (Hence the extra two holes at the top.)