Pattern and rhythm are both ways to better portray a focal point or main idea by showing a vast display of the focal point
This here is rhythm in this photo as the rocks are the main idea but they are not all the same rocks or in the same position
This is a pattern because the radiator is shown to be the exact same all in a line
The pattern shown here is within the stairs. The staircase is going upwards so the viewer sees all the stairs at once