I put so much effort in the soles that I thought the uppers needed to be something special as well. So I made the straps from sewing thread and thin metallic thread using colors I think fit well together with the color of cork. Here is the card weaving in progress (the pin is there to show the scale):
After the long piece from which I would cut the straps was finished, I measured the length of the necessary pieces, cut them and treated the ends with Fray Stop to keep them from unraveling.
The round pieces are buckles, which I cut from a length of decorative band I once bought just because it looked so nice. I didn't have any idea then what I would use it for, but it was perfect for this purpose.
Next, I glued the straps in place. This time I had to do this before finishing the buckle. The shorter part of the ankle strap was the right length at this stage, but the longer one had some extra length as it could only be adjusted after the straps were in place because of the buckle mechanism.
The next photo shows closeup of the buckle. It is sewn in place with the ends of the thread glued to the inside of the strap to keep them out of sight. The other part, attached to the shorter ankle strap, is just a piece of gold plated metal wire bent to 90 degree angle in the middle. The wire goes through the strap and the other half is glued to the inside of the strap. To close the buckle, you just put the "spike" into one of the holes in the buckle.
Finally, here is a picture of the finished shoes:
