The iconic valentine shape possesses a perfect bilateral symmetry, simultaneously expressing the distinctly different concepts of "one" and "two." It is one shape, but it has two equal halves. It has two sides, but only one perimeter.

What happens when two separate beings meet and touch edges? Does the seam between them temporarily disappear? What happens when one person watches another person dance—do the neurons in each brain really mirror one another, forming a valentinelike symmetry?

And we have other questions...