In a night mirror hall, light grains launch from left gates and ricochet with changing angles. Drag a slim capsule seam on the right wall to catch them mid-seam—glancing edges do not count. Faster grains score higher tiers. One miss dims every mirror and ends the run. Later waves fire from multiple gates into a shorter seam. Endless catching demands perfect returns.
Slide a right-wall seam to catch ricochet light; miss once to fail.