Hold out your hand flat, palm facing straight up. Now tilt it at any angle without going perpendicular to the ground, but let’s just use 45 degrees for example.
With your hand tilted backwards just a bit, but still facing upward overall, look across the room and you can predict where you would need to squat down to see the palm of your hand even if you were on the ground.
This shows light can travel in a straight line from that spot on the ground to the palm of your hand even though your palm is still facing upward overall, albeit at an angle of 45 degrees (and there is a spot on the ground that works at any angle, but the spot is farther away if the hand is tilted less).
Hold out your hand flat, palm facing straight up. Now tilt it at any angle without going perpendicular to the ground, but let’s just use 45 degrees for example.
With your hand tilted backwards just a bit, but still facing upward overall, look across the room and you can predict where you would need to squat down to see the palm of your hand even if you were on the ground.
This shows light can travel in a straight line from that spot on the ground to the palm of your hand even though your palm is still facing upward overall, albeit at an angle of 45 degrees (and there is a spot on the ground that works at any angle, but the spot is farther away if the hand is tilted less).