Make me think of this and optical illusions.<p><a href="http:&#x2F;&#x2F;www.ritsumei.ac.jp&#x2F;~akitaoka&#x2F;index-e.html" rel="nofollow">http:&#x2F;&#x2F;www.ritsumei.ac.jp&#x2F;~akitaoka&#x2F;index-e.html</a>