This Corner LED is a very simple design that prints pretty quickly. I printed it on a Bambu X1 but if you have a smaller build plate then I would scale down all the parts equally to fit. On the Bambu, I had to print them at an angle flat.

They attract to the corner of the wall via TWO push pins at the top and bottom of the extending arms. I just put some hot glue in the hole and stuck a push pin in. 

For this build, I used an ESP32 and WLED to get more effects and uses out of my light.