The Guardian – Alex Bellos
“I was alerted to sandwich sudoku by crossword champions Mark Goodliffe and Simon Anthony, who run the YouTube puzzle channel Cracking the Cryptic. (Mark has won the Times crossword championship 11 times). They featured sandwich sudoku in March, and were stunned to see the video clock more than 500,000 views – about one hundred times more than than what they normally get for their sudoku clips.” (more)