Then you should be able to present a scale diagram that shows a dime standing on its edge on the ground obscuring an elephant but still has light traveling in a straight line. Would you do that for me?
This is not to scale, but it would look something like this:
The dime is at the horizon line, and therefore at eye level with the observer
The blue lines radiating away from the dime are the dime's
shadow, that is, the dime's size in comparison to the elephant. Once the dime and the elephant are sufficiently separated, the dime will obscure the elephant, just as you can obscure a nearby elephant with a dime by holding it out in front of you with your arm.
The analogy that the dime's image casts a shadow upon all bodies beyond it is apt. The image of the dime radiates outwards, just as a shadow does, growing with distance. We do not see a black shadow on the elephant because, if you are in a room with a light source behind us and hold out and align a dime perfectly with your eye, you will not see its shadow on the wall, just the dime. And if we bring the dime closer or further from our face we can obscure more or reveal more, making the shadow bigger or smaller, illustrating that the image
grows and radiates outwards.
Per straight light rays, consider: You are standing in a room and hold out a dime in front of your face, entirely obscuring a television on the wall. How could the television be obscured if the television is much larger than a dime and light travels in straight lines? The answer, of course, is that the image of the dime radiates outwards with distance, via natural laws of perspective, allowing it to obscure televisions and elephants. None of it is to say that the light from the television is not traveling straight, but the dime is just aligned with the eye and obscuring it. Going reverse from television to dime, in assessment of the path of light, the operation is simple: If there is something obscuring the eye, the light will be obscured.
The operation from eye to dime to elephant is actually also simple: If there is something obscuring the elephant, the elephant will be obscured. But considering that this seems difficult to comprehend, this is neither here nor there.