There are great performances where a group of people, whether small or large, forms a shape or different shapes together; and you can usually see the shape from bird's eye view. It is usually like a dance performance and the performers sometimes mimic the motion of real-life events or living beings; or form the shape of a still object.
The following image is an example from a bank ad where a group of white-dressed people forms a heart shape and also mimics the rhythm of the heart:
Here is the video of the bank ad where you can see the other shapes that they form:
https://www.youtube.com/watch?v=Z_fYJL40Ork
Another form of this art is performed behind a screen where a back light is used to project shadows of the bodies of the performers on to the screen to form seemingly impossible images.
The following image is an example from the performance of the group named Attraction when they performed on the show Britain's Got Talent. The elephant shape is formed by a group of people.
Here is a video where you can watch a performance of them on Britain' Got Talent: (start from 1:20 to skip the bibble-babble):
https://www.youtube.com/watch?v=UvvkJrKKYF8
There are words like collaboration and teamwork but they are too general and don't indicate any form of art. I tried searching with keywords like human, shape, group, dance but couldn't find anything that fits.
I think there might be a general term for this kind of art or formation. (although, there might be specific terms for the examples that I gave; but in the end, it is the same logic from different viewpoints.)
Best Answer
1. For the first artistic display, I would suggest mass choreography. A mass is a name for a large group of people while choreography means a sequence of steps and movements in a staged dance performance. If you Google mass choreography there's a choreographer called Penny Jones who seems to specialize in this form of dance composition. Watch the Arbank, a Turkish bank company, TV commercial.
It's by pure fluke, I discovered who the choreographer is for this TV advert.
There is another dance term called tableau which means a pause during or at the end of a scene on stage when all the performers briefly freeze in position. The website about.com says
One renowned American musical choreographer during the 1930s was Busby Berkeley
2. The term silhouette means a representation of someone or something showing the shape and outline only, typically colored in solid black.
The expression silhouette performance seems to encapsulate the art form presented by the BGT entertainers Attraction.