#Figure out how the obstacle works
Figure out how the obstacle works
Is there a spell that detects whether there is light or heat? Or maybe there are metal wires that expand to touch each other when they are hot and hence an electric circuit is formed?
Once you know how an obstacle works, there will be multiple ways to circumvent it and the ways can be detected by suitable methods. Also, you do not need to solve the problem before play if you know the mechanisms.