Anonymity simply calls for a figure to be unrecognizable as an individual, a photograph the back of someones head would render them completely anonymous (well in most cases). This exercise, however, is looking for people to support the structure of the photograph without dominating. Ideally the people in the frame should help to tell the story.
My first image is a story telling image. A woman in a seventies wedding dress speaks to a man in a badly fitting tuxedo, both standing opposite a traditional looking southern German church. The lack of their faces in the frame keeps attention on the church and the tableau in the image. Assumption is that they are taking a break from a service or waiting to go in, why are they here. Reality is that they are actors in a drama that is using the church and they are enjoying a cigarette break. The actress hid her face when I raised the camera deliberately rendering herself anonymous and unintentionally helping my scheme.
My second image is a road bridge over the the river Isar. The composition is dominated by the ongoing sequence of lines running across the frame, tram lines, road markings, bridge structure, and the overhead electrical cables for the trams. I could have taken better care to align the shot to keep things more square to the frame. However the point of the image is the inclusion of the two cyclists crossing the bridge, adding interest and some movement into what would otherwise be a very static frame:
Image 3 contains two different ways of hiding identity, the person on the left is walking away from the camera and is slightly blurred, whereas the people in center frame are silhouetted and far away, adding human presence and scale to the building:
My fourth and the last image requested by the text asks uses motion blur to imply human activity without properly resolving it. Not all figures in the frame are blurred by the 1/8s shutter speed, but are otherwise made anonymous by the low light of this early evening scene - part of the work up for Assignment 4.
Whilst appreciating that the brief asked for 2-4 images, I want to add these as an addendum. Another way to make a figure anonymous is to heavily over expose them. This rarely works but is an interesting technique. The critical element is to show enough detail in the foreground or background to contain a degree of placement. These two images are taken from within a large underground passage looking out into the light. I have exposed for the light reflecting from the floor in the foreground and then raised the camera to shoot people entering and leaving the passageway: