Expanding on my comment, if you start with this Splay Tree and insert 5, here are the steps to get it to the root:
2 2 2 2 2 5
/ \ / \ / \ / \ / \ / \
1 4 1 4 1 4 1 4 1 5 2 14
\ \ \ \ / \ / \ / \
14 14 14 5 4 14 1 4 6 18
/ \ / \ / \ \ / \ /
6 18 => 6 18 => 5 18 => 14 => 6 18 => 17
/ / / \ / / \ / /
17 5 17 6 17 6 18 17 15
/ / / / /
15 15 15 17 15
/
15