interesting thing that happens for me with this section:
let subviews = [UIColor.gray, UIColor.darkGray, UIColor.black].map { (color) -> UIView in
let v = UIView()
v.backgroundColor = color
return v
the colors all look like the same shade of grey. Then, when I test what is happening by changing the colors to red, blue, green, respectively, I can see that the colors are there, but super faint, almost like a light that is far away, instead of appearing like a solid color