Sunglasses

Tap them (the frame or a lens) to fold the arms, flip the glasses round and darken the lenses.

These are round glasses with light-changing lenses. Special molecules in the lenses change shape in the sun's ultraviolet light and start to absorb light, so the lenses turn dark outdoors and clear again a few minutes after you go inside.

The frame comes from a detailed 3D model of real vintage spectacles. Tap them and the arms fold in on their hinges one after the other, the glasses flip over to face you and the lenses darken from clear to deep gray, then everything unfolds and clears. Pick a flag in the top bar and the frame wears its colors.

This link opens it in the Playground. To put it on your own page, add the element and one script tag. Every option.