Sending children out with digital cameras to find specific examples of a concept is an excellent way for the students to demonstrate understanding of a concept. Choices for taking pictures include iPads, iPods, cameras, phones, etc. You must decide the easiest way for students to bring their photos to a computer for printing or incorporating into a book.
For middle to upper elementary school children, compiling those photos into a simple movie with titles and descriptions of each concept is also way to improve comprehension of key ideas.
Another interesting way to share shapes and geometric concepts found in the real world is to use on of the many free apps that make collages out of photos. Most let you add text. Create displays in your classroom of the various collages!
The following pages have rubrics for a movie, book, and collage project. Rubrics included have options.
A rubric will have specified geometric concepts and then a following page will leave the concept lines blank so you can fill in what you specifically want the students to focus on.