Chapter Two: Coordinates of the Wing Bone

A seamless door waited at the end, engraved with three images: a falling apple, an orbiting planet, and a person standing upon a warped grid. "Newton, Kepler, general relativity?" Su asked. "Not a chronology. Three layers of understanding for one force." Three dials were set into the door. The first was marked mass. The second, distance. The third had no unit. Lin set mass to two and distance to one-half. The third dial lit. "Gravity follows the inverse square of distance. The answer should be eight." He turned it. The door remained shut. The corridor tipped sideways—not because the structure moved, but because gravity rotated ninety degrees.