Oh man, making a 7-segment display was my favorite question to ask frontend developers. Eventually turning it into a real clock if they were fast enough. Captures lots of basic CSS positioning, JS timers behavior and general ideas like breaking things into components etc
I'm guessing when you say "ask frontend developers" you mean "at job interviews". But I like to think you mean something like "at cocktail parties" or other social situations.
I'm choosing to imagine a bomb-defusal movie scene, where the protagonist must correct the layout of the countdown timer to save the day.
I'm reminded of Chuck disabling a bomb by surfing to a malware-infested webpage: https://www.youtube.com/watch?v=ddtpyR6WIlY
Man where were you at when I was getting asked questions "to see if you've prepared for the interview" with leet code for damned UI frontend positions... I loved answering your type of questions and most companies would not do this for some reason.
I hate leetcode type questions. It's like "math Olympia" questions I had to deal with as a kid. Either you have seen the problem (or a variation of it) or there is no way of coming up with a solution under pressure.