Light travels in 3D space and beyond 3D space. so it does not always travel in a straight line.Beyond 3D it travels in a straight line until it reaches another 3D.so speed of light is not constant it depend upon the resistance offered by 3D space ,beyond 3D and next 3D.
We can not perceive what would be beyond 3D.If we assume this ,then light must escape from the black hole too, like eddy currents of lights.And block holes might take a shape of network of irrigation pipelines with T joints.This also leads to the imagination of curved universe and multiple universes and set of universes having a shape of a slice of a solid object.