This image of simple geometry is ineligible for copyright and therefore in the public domain, because it consists entirely of information that is common property and contains no original authorship.
Article 5. Works not Attributed to the Subject Matter of Copyright
Copyright shall not apply to:
1) ideas, procedures, processes, systems, methods of operation, concepts, principles, discoveries or mere data;
2) legal acts, official documents texts of administrative, legal or regulative nature (decisions, rulings, regulations, norms, territorial planning and other official documents), as well as their official translations;
3) official State symbols and insignia (flags, coat-of-arms, anthems, banknote designs, and other State symbols and insignia) the protection of which is regulated by other legal acts;
4) officially registered drafts of legal acts;
5) regular information reports on events;
6) folklore works.
Hence it is assumed that this image has been released into the public domain. However, in some instances the use of this image might be regulated by other laws.