The only thing I forgot to put into the cutting of the slots for the Celtic knot is to make sure that the insert wood is the same kerf as your saw blade and also not to cut completely through the blank, but to stop and leave about 1/16" or less so that when you glue it all up with each cut it will bend, with a little persuation, so as to put the insert in but when you clamp it it doesn't move!!
Get my drift?
Gud 'ere init!