Hi, OP. Rule 4 requires attribution (or an attempt), which this post kind-of-sort-of has via the signature. However, most won’t recognize it, and there are at least two other prominent "Ellis"es if you try to search for “comics” (Adam (comic strips) and Warren (comic books)). Nothing you did wrong; we just like to credit artists as much as possible so people can find more of their work.

This is by cartoonist Ellis Rosen. You’re free to edit this into your post, but I can leave this stickied which works about as well.