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:
Fanosingercycle.svg en Fano plane The numbers for the points black and the lines blue are chosen thus that the plane appears to be the plane generated by perfect difference set see the article ams org pdf THEOREM IN FINITE PROTECTIVE GEOMETRY AND SOME APPLICATIONS TO NUMBER THEORY by JAMES SINGER The arrows red show generator of