Presenting Sudoku Ripeto and Custom Sudoku

This is a short description of Sudoku Ripeto and Custom Sudoku, the first Sudoku variants with repeated numbers and letters, respectively.

Gathering for Gardner's Gift Exchange Book

Sudoku Ripeto and Custom Sudoku are featured in the Gift Exchange Book following the Gathering for Gardner 13th Conference, that was held in Atlanta in 2018. The book is available for download here.