Cannot recall where I first saw it but we have been making these things for years now. Toilet paper tube + 2-3 binder clips (depending on size of clips). Clip one med or lrg or 2 small at one end of the tube to hold it shut. Clip another on one side and fold one silver arm up to create the hanger. Fits easily over a push pin. We have these on each corkboard and several by the kids’ desk. Yes, you can write on the tube to jazz it up. We also sometime staple the end shut and just use the binder clip for hanging.