In Graphviz, can I adjust arrow pointing to rectangle's boundary?
<p>Can I adjust arrow pointing to rectangle's boundary? I want to describe a stack pointer. Thanks! 
Like this:
<a href="https://i.stack.imgur.com/Q6VmA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Q6VmA.png" alt="enter image description here"></a></p>