My curiosity got the better of me and I went ahead and purchased one of the bracelets from the seller on Ebay. I have decided not to take it apart at his time, but make a few notes on the apparent construction. The alternating square knot is what is used to construct the body of the bracelet. The maker used a four-holed button with a depression, in which he melted the ends of the 550 cord. I believe the construction consists of two pieces of 550 cord, as you have stated, make a overhand knot in one piece at half-way creating a loop, then the maker looks to have used the other piece with the alternating square knot to create the body. He finished by running the ends of all four cords though each hole of the button and then melted the ends into the depression to hold it all together. Pete