One optical illusion that challenges our notion of truth is a picture that looks like Albert Einstein close-up but Marilyn Monroe from far away. See it on the 1, 2, 3 Optical Illusions website, along with the Wavy Lines Illusion, the Gradient Illusion (two bars of the same color appear different, because of where they are placed), the famous image which is both two faces and a vase, and the Kanizsa Triangle.

On the Optillusions website, find more ambiguous images such as a musician/girl’s face and a picture which makes sense either right-side up or upside-down.

The artist M.C. Escher’s symmetry drawings simultaneously show multiple, logically incompatible, perspectives; see some on a website devoted to Escher or obtain books from a library.

The website Discover UU offers a broad and diverse set of links to blogs, podcasts, and more, collectively representing a search for truth and meaning under “the pluralistic spiritual umbrella of Unitarian Universalism.”