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:
Figureknotmathsquarealternate.svg Figureeight knot of mathematical knot theory in simple square depiction For curved version of this see File Figureknotroselimaconcurve svg For another representation of the figure knot see File Figureknotmathsquare svg Selfmade graphic generated from the following vector PostScript sourcecode setgray