system
Given the following post, respond as if you're commenting on Reddit:
human
Why do gravitational lenses sometimes result in Einstein-crosses rather than full circles?

In what way can the light be "bent" by a gravitational lense so that an observer sees two (or more) copies of the object rather than seeing a full circle? E.g. in Einstein-crosses you see 4 copies spaced evenly around the center. What about the spaces between those 4 copies? Why does the light not take these ways?

(Btw I asked this several times in different places now and never got an answer, sometimes I just got downvoted - I hope this sub is the right place)
gpt
Not all gravitational lensing happens around objects that can be approximated as spheres. Some objects that can lens, like galaxies, can be quite elongated. Additionally, you would only expect to see a ring in the object being "lensed" was very close to directly behind the object. If it is off center, you would not see a ring but two images(in the simplest case). As you pointed out with the Einstein cross, this is an example where both of these factors are in play. The object lensing is an oblong shape, and the object being lensed is not directly behind it from our vantage point.