Isotropic line

Okay kiddo, so an isotropic line is like a special line that points in all directions the same way. You know how a flashlight shines its light in one direction? Well, imagine if that flashlight could shine light in every direction at once, like a big bubble. That's what an isotropic line is like - it's a line that has the same amount of "stuff" (like light or energy) going outwards in every direction. It's kind of like a big hug around a point in space, giving equal attention to everything around it.