Q: Why are their gaps in between chapters without DDL?

A: As I am busy sometimes, I skip some chapters and as I did not do them, I can not post a link for them.

Q:  Are you interested in joints?

A :  I am interested in joints, but what I can mostly offer is just editing.  So if that’s what you need, I might be interested depending on the project.

Q: Why have some pages for projects not been updated in a while?

A : I hired someone to update it, and I guess he’s busy. But if you look through the entries, you should be able to find the link for the chapter of whatever it is you want.