In case OP doesn't respond, I imagined a bit of wood with "keyhole" shaped slits in it. Probably something like this: https://images-na.ssl-images-amazon.com/im

In case OP doesn't respond, I imagined a bit of wood with "keyhole" shaped slits in it. Probably something like this: https://images-na.ssl-images-amazon.com/images/I/71K4bZIM-pL._SL1500_.jpg https://images-na.ssl-images-amazon.com/images/I/71K4bZIM-pL... or maybe this https://dclwoodworking.files.wordpress.com/2015/09/img_1312.jpg https://dclwoodworking.files.wordpress.com/2015/09/img_1312....