Woof, infodump!

Joyce is “subject 135” because in early pre-Roomies! stories she was the commander of Squad 135, which was a rival to Walky’s Squad 128.  In It’s Walky!, Squad 135 would be commanded by Daisy instead.

Professor Doc also mentions teaching high school science classes, which is a reference to his appearances in my high school strip, Sly Sirs, which aren’t in continuity with this anymore.  He just taught somewhere decades ago, okay?