Hubble image of Arp 70, also known as VV 341.

In Arp 70, a larger galaxy with two well-defined spiral arms interacts with a small companion. Such interactions have been linked to the production of grand-design spiral arms.

Credit: NASA, ESA, STScI, J. Dalcanton, Judy Schmidt
https://www.flickr.com/photos/geckzilla/48320643492/