CD light echo positions in spherical coordinates φ vs. radius r. Shell (dark gray) echoes are plotted with circles, filled for those east of the line of sight, and open for those to the west. Radial (medium gray) echoes are plotted as crosses, and the small subset of WFPC2 echoes to the northwest (light gray) by asterisks. The best‐fit lines through the east and west shell echoes are indicated by solid and dotted lines, respectively.