Nothing fancy, this is a nice way to tidy up your working place by not leaving your backpack lying on the floor (bed, chair or whatever).  Given that I had designed and printed a similar hook to hold my headset, I decided to slightly change the parameters and turn the model into a backpack hook. 

The model was made with freecad (https://www.freecadweb.org/). It is fully parametric and free for you to download. If you want to tinker with the model, it should be as easy to adapt as possible (basically, it amounts to editing a spreadsheet). 

I hope you'll like it … and if not I'm cool with that too. Have a good one