The first gravitational lensing (by an ordinary point-like object, and therefore distorted) was observed in 1979 by the Jodrell Bank telescope, the UK. It's a double quasar Q0957+561A,B. Normally, the oscillations of one image A are mimicked by the other image B roughly 417 days later, because of the different lengths of the two paths. But recently our Harvard astro-colleagues have observed some additional, 100-day-long oscillations in intensity (plus minus 4% or so) which were repeated by both images roughly four times without any time delay. Well, it's the right moment to insert a link to the paper about these strange oscillations: