Ring

Shutter Speed 1/500 F11 ISO 800

The stump of a branch has rings of bark grown around it. 

Right Triangles

Shutter Speed 1/250 F11 ISO 400

The supports make right triangles with the upper beam against the school building. 

Semicircles

Shutter Speed 1/250 F11 ISO 800

The lines of the tree bark make semicircles from the point of view of the photo.  

Ovals

Shutter Speed 1/250 F11 ISO 800

The blurred light on the ground falls in ovals between the trees. 

Polygon

Shutter Speed 1/500 F11 ISO 800

The outcropping of the building is in the shape of a four-sided polygon. 

Trapezoid

Shutter Speed 1/500 F11 ISO 800

The workbench is made up of trapezoidal wood pieces. 

Circle

Shutter Speed 1/250 F11 ISO 200

The top of the lamp makes a circle against the sky. 

Cones 

Shutter Speed 1/250 F11 ISO 800

The traffic cones are stark orange triangles on the ground backdrop. 

Triangular Prisms

Shutter Speed 1/250 F11 ISO 800

The ribbed underside of the eaves are in the shape of upside down triangular prisms. 

Rectangular Prisms

Shutter Speed 1/250 F11 ISO 800

The two-by-sixes making up the bench are in the shape of rectangular prisms, which make other polygons with the intersections in the photo.