Polymer Clay Buttons

I have been experimenting with using my laser cutting machine to create Celtic designs on polymer clay buttons. Polymer clay is an easily modelled, coloured, plastic clay that can be "fired" in a domestic over. At only 120 degrees celsius, the plastic particles bind together to form a relatively hard piece of plastic. I use this to create many of the buttons that feature on my bags (see my website). Mostly these are just colours marbled together and shaped by hand, but I am trying to be more adventurous.
I have tried three different methods with the one design. Left and middle, a very thin layer of orange clay was cut on the laser cutting machine and the pieces laid onto a brown clay base. One is the negative shape, the other the positive - so no waste! In the middle button, there is a middle layer of marbled brown and beige clay between the orange and brown clays. For the button on the right, there is an engraved line as well as the cut lines, to create the border which shows the "unders and overs". Once the pieces were all in place, the triangular shapes were cut with a tissue blade. I laid the buttons upside down and fixed brass button backs in place with a small ring of clay before baking in the oven. The technique needs a bit of refinement, but I think it has potential. In due course, some of these buttons will appear on my bags, but I think there is too much work for it to be generally cost effective - most of the buttons will continue to be simple marbled colours and hand-shaped.