When an object casts a shadow, the resulting shadow shape is dependent on a number of factors beyond the characteristics of that object itself. The angle and direction of the light, intensity of the light, number of light sources, and the shape of the surface onto which the shadow is being cast all play a role in the resulting shadow. When the surface in question is varied, the shape of the object casting its shadow gets transformed and distorted. Stairs, with their multiple planes, bend shadows that fall onto them into zig-zaggy shapes.
At MIT, inside the Stata Center. April, 2010.
At MIT. April, 2010.
In New York City, going up to the High Line. March, 2012.