I needed a small corner shelf which i can expand in height, just as i need it. I added a second plat with screw holes, so you can screw the shelf to a wall. I haven´t printed the plate yet, cause with 3 levels you don´t need it. But if you want/need to print it, print it standing up with the same settings (plus activating supports) as the normal plate.

I added longer legs for the modular shelf, the new ones are 20cm long, you can print them with the same settings as the shorter standard legs.