Very good point. I have never seen an elevator with “NAHORU” and “DOLŮ” buttons in my country, always 🔼/🔽 – to the point, reversible and blind-friendly. Most elevators just have a single, unlabeled “REQUEST” button on the outside, though – most people take stairs so elevator efficiency is not a great concern; you can also see a ▲/▼ symbol on the screen and only press the button when the elevator is in the desired mode. Also, no such buttons inside the elevator, always floor numbers even if there’s just two.