What's seeing without light? Tropism is the reaction, in a definite manner, to stimuli.
I respond to light. I won't even begin to get into the different kinds of light here but when it works, it works. These examples are from a walk in an industrial area under a bridge ramp between two buildings. The late afternoon light was slotted between the ramp and a north facing wall. The rays were parallel to the surface casting these gorgeous shadows from some terribly beautiful protest posters. Each 1/4" peel threw a dramatic shadow down the wall. There was a moving feeling of vulnerability and fragility to these robust declarations to the world. It was late summer and I have been back many times since. They're all gone now and it's never looked this way again. Carry a camera.