Is it just me? Framing something like this as a brainteaser (which is fundamentally what "magic tricks" are) makes it less interesting to me. Show me a proble

Is it just me? Framing something like this as a brainteaser (which is fundamentally what "magic tricks" are) makes it less interesting to me. Show me a problem which can be solved by applying parity or similar robustness principles and then it starts becoming appealing.