Seeing has a geometry that we often ignore, until something unusual catches our eye.
Though we normally can’t see them, rays of light always follow straight-line paths.
These straight lines of light converge on our eyes from all directions.
Although we see a three-dimensional world, each of our eyes only receives a tiny, flat projection of light.
Shadows are distorted 2D projections made when light shines past the edges of 3D objects.
The straight-line geometry of seeing gets more complicated when light reflects, especially when the reflection isn’t flat.
What you see depends on where you stand—objects that are far away usually look much smaller than those nearby.
Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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