I had an alcove in my dining room that was dead space, and it was too shallow to put a piece of furniture there because it would encroach on the doorway entrance to the room. So I decided to instead install some shelves.
I used some 1" thick pieces of melamine - they were actually faulty desktops at my place of work - the holes were drilled in the wrong place for the desk frames, so the supplier replaced them with new ones so these were all going to be disposed of, and I asked if I could take them home.
I wanted to cut the shelves at an angle to match the shape of the alcove, so I placed a straight edge against the two front corners and used a bevel guage to measure the angle which I think was around 80 degrees. I could then mark this up on to one of the pieces of melamine, and also mark up the desired depth for each side of the shelf as well as the length of the front of the shelf. I cut it out on the bandsaw which left a really nice clean cut with no chip out.
I had to cut out the corner to fit around a piece of architrave surrounding by doorway too. Once I had one shelf that fit nicely, I could use it as a template to cut out the rest of the shelves. I made some shelf supports out of some scrap pieces of blockboard I had in the workshop, and drilled pilot holes on the rill press.
Then I could install the shelf supports and shelves, which were screwed down to the shelf supports to make them more solid.