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As I lay in bed this evening a few cars have passed by and my blinds are down. As they come down the street, you can see a sliver of light on the wall on the side of the room that is in the direction they are traveling (this is wall A). As they get closer and closer to the window and eventually pass it, the light moves from wall A to its adjacent wall B, and eventually to wall C which is adjacent to B.

Since the source of light is essentially traveling a line that is parallel to the window, why does this movement occur?

I’m thinking perhaps refraction but I’m still learning the basics.

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Refraction isn't needed to explain this. If you draw a straight line from the car's headlight to your window (the part that's not covered by the blinds), and extend that line into your room until it hits a wall, then that's the part of the wall that will be illuminated by the cars headlight. Here's a picture:

headlight_on_wall_v2

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