I thought I'd replied to this post, I must have closed the page instead of hitting post.
That is a huge amount of work, the shape is very smooth in its line and the idea of the piercing out between the grain lines and all the irregular shape and work that entailed is clever.
2 questions;
I can see it is a piece of branch (or small trunk) but the rings, so is that hole a knot?
There is also more light shining through the lower part, is that where you got a bit thin or is it where the light travels through the parallel grain easier?