The name of the puzzle is jigsawdoku-sudoku.
Load init-jigsawdoku.
Ok.
The name of the action is write-1-to-4.
You can write a number that is between one and four onto an empty location.
If the value of a location is absent then the location is empty.
The solution has four steps.
Load fail-jigsawdoku.
The name of a failure is same-row-value.
Ok.
If the row of a location is the row of a location and the value of the former location is the value of the latter location then you lose.
The name of a failure is same-col-value.
Ok.
If the column of a location is the column of a location and the value of the former location is the value of the latter location then you lose.
The name of a failure is same-section-value.
Ok.
If the section of a location is the section of a location and the value of the former location is the value of the latter location then you lose.
Load final-jigsawdoku.
The name of the goal is all-filled.
Ok.
The goal is that all locations are filled.
If the value of a location is more than zero then the location is filled.
Done.
No.