See demonstration: https://jsfiddle.net/jmk2142/dLb07fr2
TINKER - attempt to repair or improve something in a casual or desultory way, often to no useful effect.
It's funny that the problem is called a "tinker" problem in that tinkering is usually messing around with stuff without a very planned way. I think, when we use the word tinker, it's really to emphasize the spirit of the activity; that is to not feel too pressured into treating it like a test of your ability. It's really meant to be an opportunity for you to explore and have fun messing with stuff while using the guided questions to challenge your understanding.