It would be great if there would be a floor in the lift, animated with armorstands

I am really far behind in what the api is capable of -- this code base goes back to the alpha days. Back then the moving floor was jerky as it was just rapidly creating/uncreating blocks.
Do you have a link on an example/tutorial?
The only catch I am worried about is that, currently, anything in the elevator shaft that isn't part of the lift is held in place until the lift ride is over. There were some edge cases of people getting ready to use the lift, but someone on another floor turned it on just before them and they would fall to their dooms.