A Striped Prism

I noticed a smooth wooden coaster resting tilted against a small glass paperweight. The afternoon sun was shining straight through the glass, casting a pale ribbon of bent light right across the braided seat. I paused, tilting my head to see if the glow would slip away if I stepped closer. Taking two cautious steps, I pressed my chin against the coaster's smooth wooden rim. It slid down flat with a soft clack, and the bright light instantly split into a neat fan of amber stripes across my front paws. Can this quiet glass wheel weave little sun paths whenever it rests?