Testing hypothesis: For every constraint, there is an equal and opposite anti-constraint. Research into quadruples has turned up anti-quadruples in far greater quantities than theory suggested. Further research will be required.

There’s really no point in having two fully-populated quadruples clues in a box. They only touch seven cells between them, so giving you four digits is overkill.

There are eight L shapes in this puzzle. No, I didn’t forget the green ones: two of the peach ones aren’t L-shaped. There are ten lines bent into right angles, but two are bent in a different direction from the others. And I don’t care what anyone says, it’s not an L if the horizontal bit is longer than the vertical bit!

I know how I solve this puzzle, but it’s fun wondering how others will. Top to bottom? Left to Right? Odd-numbered boxes first? Alphabetically? Any order that leads to the fully-zipped puzzle is great.

These Zipper lines, like most Zipper lines, are made up of pairs, with or without a center digit. Unlike most Zipper lines, each is one of a kind. Not just in which pairs make up the line’s value in which order, but in the values themselves.

Irish pub cuisine, or a Gattai-3 Sudoku puzzle? You decide!

A new variant: Autophobic digits are terrified of themselves while at home. It’s the opposite of the previous puzzle’s Autophilia.

A new variant: Autophilic digits are extreme homebodies, and while at home, they love to stay in their rooms, never leaving for any reason.

Cloned areas can be large or small, but of course we balance things out by having fewer of the small ones and more of the large ones. Wait, that seems backward. But there it is: the large the cloned area, the more clones there are.