It's way overkill to use a cutting machine or to take a trip to a copy center for a simple rounded square shape. Printing on specifically designed sticker material designed for inkjet printers is also way easier than cyoubx's old video method.
I looked online and I found hole punches for squares as well as rounding corners, each of which is under $10. I'll try it out when winter holiday comes.
This would make good content for a cubing youtube channel... did you know even before I knew how to solve a cube, I wanted to have a channel? I was most inspired by Thrawst. My first video was going to be on how to assemble a Rubik's Ice Cube 2x2. I didn't have a tripod so it was impossible to assemble it with one hand while holding the camera in the other. Later I broke the cube because it's the old design where you have to kinda bend the plastic to force it to assemble/disassemble. I've actually filmed a few amateur reviews on cubes, but I would only start a new channel if I got into 3D printing custom puzzles.