Have you had this happen before?

[Del the cat]

Is it just me or do you guys see it... I've put a red line just right of the line.
You can see how they match up book fashion...
I don't think it is ring as the bit that popped would be following a ring.
Chrysals do go remarkably deep.
Del
BTW:_ I just checked out Dean Torges site (thanks Mike) and found the article, excellent read:-
http://www.bowyersedge.com/patch.html
The link is here for those too lazy insufficiently meticulous to find it themselves