As you can see in the screenshot, once you plot the points for each rectangle, it becomes easier to see what's happening. In the first transformation, the rectangle is translated or slid. In the next 2 transformations, the rectangle is rotated. In the last transformation, the rectangle is dilated or shrunk. The first rectangle is the only translation.
A vertical line is any line parallel to the vertical direction. A horizontal line is any line normal to a vertical line. Horizontal lines do not cross each other.