This puzzle is designed by Stewart Coffin too. The aim of this puzzle also moving one of the beads to the other loop and putting two beads on same loop.This puzzle is a more complex version of “Sleeper stopper“. Rope arrangement is visible from photo but you can find also this puzzle in his 1985 edition puzzle craft book. Both end of the rope are fixed to the wooden block. For this you must drill a small hole according to your rope dimension and glue the rope ends into this hole. I made this puzzle from 20×20 mm ready stock. Wooden part dimensions 20x20x100 mm and rope hole is 10 mm. I advise making wooden block larger and holes bigger than mine. 20x40x100 mm wooden block and 20 mm holes may be a better dimension. Wooden beads are from a craft store. I decorated wooden block by painting with acrylic paint. I rounded corners of wooden block by sanding. You can see original puzzle made by Stewart Coffin from here. This puzzle also looks impossible to solve.