I needed an S hook for the Ikea Grundtal rack (http://www.ikea.com/nl/nl/catalog/products/70011397/), one that snugly fits to the rack. Here's a parametric model. There's a parameter for adjusting the snugness; this further closes or opens the top curve of the hook. Update: added parameter to print multiple copies. Just enter the width and depth of the print bed.An interactive version can be found at http://joostn.github.io/OpenJsCad/ (scroll down to Examples and choose Parametric S Hook) Or download the .jscad file and parse it at http://joostn.github.com/OpenJsCad/processfile.html