You probably give little thought to why the stairs in your home are built the way they are. I’m talking about how high you need to lift your foot to get up to the next step and how deep the flat tread is when your foot falls. The vertical face of a stair is called a riser and the flat step is a tread.
I’ve built many staircases in my career. I also had the good fortune to go up and down many steep ship ladders (stairs) on the USS George Washington (CVN 73). I was on board for an in-depth media tour as she carved crescent-shaped courses 200 miles off the North Carolina coast. New naval aviators were doing their daytime and nighttime qualification tail hooks for the first time. The only elevators on this huge aircraft carrier are for airplanes, not sailors.