How does a line with a slope of -2 visually differ from a line with a slope of 2 on a graph?

Both lines slope upward from left to right.

The line with a slope of -2 is horizontal, while the line with a slope of 2 is vertical.

Both lines slope downward from left to right.

The line with a slope of -2 slopes downward from left to right, while the line with a slope of 2 slopes upward.