Experiment vs Design

What's the difference between experimenting with crochet and designing?   I've been pondering this question for a while now.  The dictionary gives us these definitions:
Experiment: a test, trial, or tentative procedure; an act or operation forthe purpose of discovering something unknown.   
Design: to prepare the preliminary sketch or the plans for (a work tobe executed), especially to plan the form and structure of.
When do you feel you get to say that you are done experimenting and you move to designing a pattern for a crochet piece? I've been working on a purse for myself that I just made up to see if I could.  So I guess  you could say I'm designing a purse?  Well, the structure of the purse is nice and it's a good size.  I used 100% wool and tried to felt it but it's not quite as tight a felting as I would like so I guess I'll make the same purse but in a new yarn.  Do I need to write down the pattern notes and "viola" I'm a designer?  There is a good article written by Helen Free in the February issue of Inside Crochet with great tips on how to use the auto-correct in MS Word to write a pattern.  Have any of you out there designed a pattern?

Now as for experiments... if I only make the 1 purse is that an experiment?  Even if I write down the pattern?  I think the word "experiment" is more appropriate for what I would like to try for the first time.
When it comes to things I want to experiment creating:

• Cardigan for me
• Lacey shawl

Materials I want to experiment with:

• Wire
• Rope or twine
• Beads
• Tule