I just realized something very special about the defining color of that pony that sometimes defies the laws of physics and deviates so nonchalantly from what is considered within the spectrum of normality:

Our visible color spectrum ranges from red to violet. Red is the longest visible wavelength and violet is the shortest one. It's what you see in rainbows. BUT as you can see in the color palette of graphics programs, this is not the complete range. Blending together, outside of the would-be complete spectrum, are violet and red, resulting in pink. For our perception, but also wavelength physics, pink is not an extreme, not an in-between, but it is outside of the whole range.

A rainbow spectrum: red -> orange -> yellow -> green -> turqouise -> blue -> violet

The full color circle: pink -> red -> orange -> yellow -> green -> turqouise -> blue -> violet -> pink

In the color circle, pink is actually the average of full red and full blue (purple being just outside of blue), but it's not contained in a rainbow, because of the wavelength range. Pink is the only full color that does not result from a mix of NEIGHboooring wavelengths OR a single wavelength if you will. Because while, for example, yellow light can be a mix of red and green wavelengths OR pure yellow wavelength, pink only occurs as a mixture. There is no pink wavelength. It is a mix and middle of two extremes.

Isn't this exciting?!