I was playing around with the rectangular to polar filter and got something that resembled a button -- this image took off from that. I isolated the rim of the button and applied a bevel layer style then recombined the button and added a drop shadow. I built the shirt, placket and buttonhole with a fill pattern, a color adjustment layer and some bevels. The stitches came from a custom brush and a stroke/path action. The threads are filled rectangles with some shading.