I've tried to search for this and haven't found much. The terms around this are just too generic and generate tons of unrelated threads. So sorry if I am repeating something that's been addressed.
If you go to http://www.grypesagon.com/category/artwork/ you'll see that it's the category description with a menu listing the posts within that category on the right hand side in the sidebar.
If you click on any of those items it takes you to a page with thumbnails and such.
I already have the sidebar doing different things based on what type of page it's on.
I need to know how to code it so that when in single.php it will list the same menu it shows when viewing the parent catergory.