title: What is a rooted tree?
body: <p>What does it mean to build a rooted a tree? I read the definition in <a href="http://mathworld.wolfram.com/RootedTree.html" rel="nofollow noreferrer">here </a>but even if we assign a node to be the root, why does the tree take only the shapes below? I mean I can draw a rooted tree with 4 vertices in more that the 4 shapes below? Right?</p>
  
  <p><a href="https://i.stack.imgur.com/JMEW3.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JMEW3.gif" alt="enter image description here"></a></p>