Bonus: 0 minutes?
This clock was invented by Levi Esser, Jeroen Rijnart and Roland Donk during a lecture Interaction Design by James Boekbinder.
The idea is to help me win my tutoring student’s attention by rewarding them with skipping real time minutes when right answers are given. Therefore the tutoring moments shrink in time, time that can be spent to do fun stuff.
Also the student’s motivation to learn in their own time will be increased, because that makes it more likely to win minutes next time.