The dark-box run closes with an inversion: where its siblings raise their mouths on collars, this block’s top sinks inward to a small oval opening over a black glossy-looking interior. Heavy lava-like crust, silvery washes. Underneath, a pale square pad is incised 557.
Why does the mouth sink? Its siblings wear raised collars; this one swallows instead — same family, opposite gesture. Piece 557 of 10,000, listed at $5.57.
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