Marble

Tap it to roll it around a little circle.

A marble is a small, hard ball, usually of glass, with twists of color inside. Children have played games with little balls of clay and stone for thousands of years; glass marbles became common in the 1800s. A twist of colored glass is set in the middle of the ball while the glass is hot and soft.

Tap it and it rolls around a little circle, turning the way it rolls, so the swirl inside turns too, under a polished glass shell that catches the light at its edge. After one lap it is back exactly as it was. Pick the color of the swirl in the Splash tab.

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