Variant catalogue
These are the names pencilmark gives a puzzle when its rules match a known pattern: describe() and meta.type use
them ("Samurai Sudoku", "Argyle Sudoku"). They are a library feature, not part of the puzzle format: a
samurai file is five box_grid rules and an Argyle file a few region rules, so any reader that reads those reads the
puzzle, and no reader needs to know the names. How variants are named gives the exact matching rules; rule
families such as killer cages and thermometers have their own pages under Rule families. For an introduction to the popular variants, see Artisanal Sudoku's
basics of popular sudoku variants.
Placement variants
A placement variant adds fixed regions to one grid. pencilmark recognises it when every region it adds is present, on any board size where it is defined.
Multi-grid layouts
A multi-grid board is written as one box_grid per 9×9 grid (Houses and regions).
When the grids' top-left cells match a named layout, the puzzle takes its name: "Samurai Sudoku", "Killer Twodoku". In
the drawings, overlapping grids have different tints, so the shared boxes show as a blend. Another arrangement is a
"Multi-Grid Sudoku" and is graded the same way.
