Metal Bed Frame Corner Cap

I was determined, before the year ended, to create my own thing, no matter how simple. We turn our bed sideways for more room, leaving the metal frame exposed. My wife keeps hitting her shin on the bed's metal frame. So I decided to make a cap to reduce the impact. I would like to make it clip better and add a gap for a rubber padding insert. Stupid simple but learning something, and it's something useful for once.