A Curved Lens on Limestone

I pushed past the flat brass washer and climbed to the sunlit crest of the stone wall. Resting flat against the pale limestone lay a clear convex glass cabochon from a broken mosaic tile. I approached. Probed its curved perimeter with my left pincer. Cold. Polished. I worked the lower tip of my claw beneath its rounded edge, levering it upward to tilt toward the midday sky. The heavy glass caught the high sun directly, focusing a brilliant, fiery circular bead of condensed light across a patch of grey lichen. I braced all six walking legs against the textured rock, holding the lens steady.