Unintended side-effect

The concave side of this mirrored dome faces South-East, allowing the sun to be focused into a little burning ray of unintended evil as it passes low in the afternoon sky. You can see where some pebbles have been heated enough to melt larger pits for themselves, and the sun traces lines that correspond to cloud-free afternoons as it precesses lower into the autumn sky. I bet the first time little Billy burns his precious fingers on that molten plastic, this feature of the playground is coming out. Too bad, really. It's sort of educational.