Self-made Benham's Disc for <a href="https://en.wikipedia.org/wiki/Benham%27s_Disc" class="extiw" title="w:Benham's Disc">Benham's Disc</a>.
No machine-readable author provided. <a href="//commons.wikimedia.org/wiki/User:Ambuj.Saxena" title="User:Ambuj.Saxena">Ambuj.Saxena</a> assumed (based on copyright claims).
No machine-readable source provided. Own work assumed (based on copyright claims).