The idea is that you fold the nine squares down to a single square. The top square should be an S. The next square underneath should be a P. The next should be an I, and so forth, until you've spelled the word "SPINELESS". If you do it right, maybe a squid will appear when you unfold it?
If you figure it out, it might be too difficult to describe each step of the fold, so it should suffice to tell me how the E's and S's are ordered.
The "spineless" puzzle is my own creation, but it was inspired by a similar puzzle created by Robert Neale. I only created my own mostly because it was a fun challenge, but also because Neale's puzzle is a tad more difficult.
See my explanation of how to find the solution (actual solutions not included)
[For further reading, see "The Combinatorics of Paper Folding" in Martin Gardner's Wheels, Life, and other Amusements.]