I made this holder for the coasters project. I made two actually, one for the coasters gift and second for my set.
I thought about a few different ways of doing this. I ended up doing contrasting maple and walnut pieces and jointed them a dovetail rabbet joint. To hold them together, I made pins made of walnut. The pins are mortised through the maple and go into the walnut. It should support the joint and looks nifty. I was going to do a dowel, but a little extra work for square pins.