Diffraction

In optics, a diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams travelling in different directions. 

That's the official explanation for sunlight shining through a thin and uneven cloud cover.
The definition and experimentation of the concept of diffraction owes a great deal to a fellow Aberdonian, James Gregory, who developed further some of Newton's optics theories in the early 1700s.

I just went down a fascinating "rabbit hole" discovering about James Gregory, a fellow graduate of Aberdeen University. The concept of only focusing on one aspect of science is relatively new, isn't it? Instead they defined 'stuff' as they needed it on their journey to define other 'stuff'. Mr Gregory was also a big mover and shaker in the field of calculus, for instance.
I am reminded of my eldest, who in his desire to better describe the movement of a space rocket in a computer game he was writing, at age 11 taught himself trigonometry from maths books that his bemused parents supplied to him.