Here is one I did a couple years back - the customer wanted it to be all black, just morph out of the binding with no continuation of the purfling lines on the top edge. I dont purf the side edge at all anymore - the only real way to cut the troughs is by hand and it can be a real bear. So now I do them this way, or not at all !!!
you will note in the one photo aways down how the ebony doesnt end nicely at the corner of the armrest smile as I call it. this is because the top binding is only about 1/32 deeper than the top thickness. This doesnt happen at all if the binding and back and sides are the same wood - thats actually how I prefer to do them if I can, otherwise I usually end up darkening the armrest, or lately I actually came up woth antoher way, which is to bind the top of the armrest at full binding plus purfling depth, then it just carves right into itself all at the same level. So anyway here are some photos - the first one shows that I cut all the binding and purf channels first, all the way around. The internal block is sized to be a bit bigger than the plexi template I use to route for the ebony binding shown inlayed here.
) before I was able to get it to fit properly. The next one will go a lot faster.