R1 is red, BR is yellow.
BR is farther from 2B than R1. But, he is farther along the baseline from a perpendicular standpoint.
OBR 7.08 A runner is out when - (h) He passes a preceding runner before such runner is out;
Fed language is similarly vague in this regard, with an exception for an obstructed preceeding runner.
Can anyone provide a definition for "pass"? Its obviously nitpicky, but hey, its the end of the summer.
My guess would be a pass for the diagram above.