To make things easier to understand, I have some photos below.
Now, if I create a 4x4 tile, then extrude the outer 12 squares, I get a cup-shaped object.
But if I create a Loop Cut on this object, you can see that it doesn't reach to the inside of the object.
How do I make it so that a loop cut reaches through the entire object?
Thanks for taking the time to read my post!