Rail-Fixing Hanging Hook

I needed some kind of hook to hang my upside-down planter from a tie-bar in the conservatory and this is the result.

It clips nicely over a 16mm rod (the width lower 'slot' being a little smaller, so it snaps into place). There are then two small hooked ends over which I threaded some cord.

I initially started parameterising the design, but ended up using a bunch of hard-coded magic numbers, so if you change any of the parameters, you'll probably need to change some of the other numbers to