This idea is really simple. Even if you can maximize the area with sharp corners it might not be the most favorable surface for us to look at. I therefore suggest that whenever you see a sharp corner. You can ask yourself. What if a rounded corner would look better. Products that I think rounded corners would be suited for would be photo papers print outs, magazines, regular writing paper. For us computer nerds we could just add rounded corners for the image viewer or maybe for the whole desktop in Linux. Like an old black and white television.
For the desktop I provided my rounded Ubuntu MATE. View the image in full screen for the maximum effect. Click on the image and in Firefox press F11. If this could be done with something similar to HTML, CSS then it would be pretty cool. With such Desktop CSS you could start to adapt pretty much everything.