So I was recently handed this rock with the question of what are these things in the rock. I am unsure and as far as I know anyone who has looked at the rock doesn't know either. So I ask for any possible ideas. The rock is a limestone and that is about all I know about it. I have my ideas but I want to leave this as unbiased as possible.
It appears that the structures go through the rock in a circular/ cylindrical pattern bosed on the side and top views.