Rectangles – In geometric terms, these are less simple than a triangle, having four side and corners, but in a photograph they can seem more basic simply because they relate to the shape of the picture frame. When a rectangle in the scene or subject fits within the frame very closely it almost disappears from the attention.Rectangles have a special place in an art form that has rectangular images as the end-result. The simplest way of dividing the frame is horizontally and vertically as this automatically creates rectangles.
Circles – If triangles and rectangles were relatively easy to find, circles are much less so, and depend to a great extent on real circular objects. This limits their usefulness in photography. Nevertheless, a circular shape, when you can find it, is the tightest, most compact and enclosing of any. In other words, it imposes even more structure on the image than would a triangle or a rectangle.
• The Art Of Photography (OCA course book), Part 2, Shapes – Rectangles & Circles, p.93-94
Whilst not a required exercise, there is a requirement to look for photographs that make bold use of rectangle and circles, which I have chosen to do from within my own photo collection.
I found that it was easier to find or spot images containing circular subjects or objects than rectangular ones. I guess that’s because circular shapes appeared more immediately obvious than rectangular, which are such a common structure as to go almost unnoticed generally speaking.