Light vs. mass (model) PA (left) and ellipticity (right) for our sample of quadruply imaged quasars. The ellipticity of the main lens in B1608+656 (e_obs = 0.45 ± 0.01, e_mod = 0.84 ± 0.01) is not shown to ease legibility. Systems having a companion within the Eintein radius of the main lens are depicted with a filled triangle. The red solid line depicts the situation where the light perfectly traces the total mass. The error bars are 68% CL error bars.