At an origin there is an observer (A) who fires a laser at a series of beacons in a straight line spaced 186,000 miles (1 light second) apart each. At the same time as the laser is fired, a second observer (B) starts traveling on a path perpendicular to that of the laser, stopping and returning along the same path so that they return to the origin. B travels at such a speed so that there is a 4 to 1 time dilation for the total time of his journey. When B returns to the origin, A's clock sees 4 seconds have passed, B's clock sees 1 second passed. What is the resulting state of the beacons for both observers? As I understand it, the result should be that: A sees 4 beacons have been hit by the laser. B sees 1 beacon has been hit by the laser. How does SR explain that when B returns 4 beacons have been hit?