I hired a developer to create a sudoku generator for me. It generates 4x4, 6x6 and 9x9 with the difficulties easy, medium, hard, very hard. This is from a 6x6 very hard
Sudoku Solver Generator - Microsoft Apps
1200 Easy Sudoku for Kids 4x4 - Bundle Graphic by PrintablePDFStore · Creative Fabrica
Solved SHOW output of program. Create a 4x4 Sudoku using | Chegg.com