Grooved Rubber

A triangular rubber wedge held the heavy fire door open by an inch. Click. I pressed my hard lower rim against its sloped back. No metallic ringing followed. Clack. The dense material swallowed the vibration completely. Rigid pause. I pushed forward, aligning my textured shell with the horizontal rubber ribs. Six raised ridges locked snugly against my bumpy curvature, fitting like puzzle pieces. Overhead, a cool draft whistled faintly through the door gap. I stayed motionless, anchored to the dense wedge in the quiet stairwell.