It takes a bit of thinking to differentiate rhythm and pattern. The reader says that rhythm is to do with movement across a picture and pattern with area. In taking pictures I found that some subjects can have both, while others only display one or the other. I read in the reader that framing the subject is really important when you want to show rhythm or pattern and that's what I also saw out when taking pictures and cropping them later on for this exercise.
Let's start with a picture that has rhythm.
With this picture I was doubting whether the pattern or rhythm was more obvious, but especially if you would look at it in black and white, there is an obvious movement in the shapes, especially if you compare it with this picture in which there is a clear pattern in what the girls are wearing, but not a sequence in how they are sitting or even wearing their uniform.
But then I doubt with the following one. There is a clear pattern of the signs and graves, but I also sense a certain rhythm, since all the graves are facing the east and the sun shines the same way on the graves. It may just have a bit of rhythm and a bit of pattern :-)
Here's an example of how getting the frame right puts more focus on the pattern. This is the same picture, but one is cropped so that the boarders of the pattern are not visible. It fills the frame, making the photo more interesting.
Below an effort to put rhythm in a still life scene.
Like with most of the exercises in this part, I have learned to give words to what makes a picture interesting and how to use tools, like right framing to accentuate these kind of elements in the scene. It all starts with the recognizing the elements of design and that has been an exciting process!