While not an engineering question per se, here’s a problem where “thinking outside the box” can help lead to a solution. It’s fairly straightforward to create the number 55 by using the digit 4 five times:
Can you create the number 55 using the digit 4 just four or fewer times? You may use any mathematical operation, but no other digits.
I’m not aware of any solution using four 4s, but here’s one using just three:
