SHAPE
A shape always has length as well as width. This is shown as an limited area that is defined by some of the others elements. When lines form together, they form shapes. Shapes can be of any size or of literally any shape.
The artist that created this piece is called Erwin Wurm and he looks a lot at people fitting into small spaces and trying to fill them out.
This piece is very good at showing shape in an unusual way. This piece shows shape that has been constructed by people taking up poses that fill up spaces. Shape is brought into this because the people have had to take the shape of others around them in order to occupy the space.
This particular artist always looks and constructs things like this and occupies many different places and therefore the people that take part in these things are always made to either squeeze into very small spaces or go very high and occupy big walls.