On the subject of gravitational lensing there seems to be two rather different phenomena. The "arc" phenomena seems rather plausible to me, if light is affected by gravity which is natural then there should be able to get that kind of behaviour. But the multiple imaging stuff, seems rather strange to me, why does it occur? If you look on the wikipedia page for gravitational lensing: http://en.wikipedia.org/wiki/Gravitational_lens There are three examples of arc-like phenomena, but there is also one exampel of multiple images, the so called "Einsteins Cross". http://en.wikipedia.org/wiki/Einstein_Cross Where, for some reason, there is what looks like for different quasars (or stars, I guess you need some kind of spectra to see that they are quasars) which is said to be four different images of the same Quasar. Besides from explaining it here, it would be helpful if someone who knows more than me could write something on this on Wikipedia. There is basically only one and not very informative sentence on the subject there.