I thought that example was quite nice, and it might work with kindergarten kids. It has to be kept easy and not overwhelming, though. I'd do it like this: Firs

I thought that example was quite nice, and it might work with kindergarten kids. It has to be kept easy and not overwhelming, though. I'd do it like this: First take some simpler map that can be 3-colored and ask the child to 3-color it. Make sure it is always correct (no neighbors have the same color). Then give a simple map that cannot be 3-colored. Let the child try it for a while, try arguing together or let them try to argue why it is not possible. Maybe even start with 2-colorable first, and move up slowly to 3 and then to 4. Mentioning that 4 always works is optional. Depending on the child's patience, they can even try coming up with the 3-counterexample themselves. It can be a back-and-forth of challenges and solutions between the child and adult.