The phenomenon is created by the shifting play of light and shadow over the lunar surface.

An enormous 'X' and 'V' will grace the moon's surface tonight. Here's how to see them

Source: space
Source Link: https://www.space.com/stargazing/an-enormous-x-and-v-will-grace-the-moons-surface-on-july-2-heres-how-to-see-them