This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Betaskeleton.svg skeletons of set of random points in square The heavy dark edges are the skeleton for while the light dashed blue edges are the additional edges for own David Eppstein Source code This image was created with the following Python source code and then recolored and converted to SVG in Adobe Illustrator from