Hi,

The two icons on the left side (number 1 and 2) are rotating block icons. If they are opened, they will change from horizontal to vertical (icon 1) or vertical to horizontal (icon 2). The two icons with the black stripes are non rotating icons. The rotating icons are created for color blind people so that can actually see if the valve is opened/closed regardless of the color.

We tend to use the non rotating icons because it looks a bit stupid, but it's perfect for color blind people.