How to run

swipl -s sudoku.pl
start.

Then follow instructions

Here are some example inputs in solve mode

# one cell missing
[
    [1,2,3,4,5,6,7,8,9],
    [4,5,6,7,8,9,1,2,3],
    [7,8,9,1,2,3,4,5,6],
    [2,1,4,3,6,5,8,9,7],
    [3,6,5,8,9,7,2,1,4],
    [8,9,7,2,1,4,3,6,5],
    [5,3,1,6,4,2,9,7,8],
    [6,4,2,9,7,8,5,3,1],
    [9,7,8,5,3,1,6,4,0]
].

# all zeros
[
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0]
].

# Example NYT Sudoku from April 5, 2024
[
    [0,3,0,5,6,0,0,7,0],
    [9,0,0,0,0,0,0,5,0],
    [0,6,0,8,2,0,0,0,9],
    [1,0,0,0,0,0,0,0,0],
    [0,0,0,0,9,2,8,0,0],
    [0,0,0,0,0,8,0,9,7],
    [0,0,7,0,5,0,0,3,2],
    [5,0,0,3,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0]
].

# Invalid puzzle
[
    [3,3,0,5,6,0,0,7,0],
    [9,0,0,0,0,0,0,5,0],
    [0,6,0,8,2,0,0,0,9],
    [1,0,0,0,0,0,0,0,0],
    [0,0,0,0,9,2,8,0,0],
    [0,0,0,0,0,8,0,9,7],
    [0,0,7,0,5,0,0,3,2],
    [5,0,0,3,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0]
].