Sergey Crane is known as Zegres (aka the Riddler) and introduced riddles with his Sudokus as the initial break-in. His first feature on CTC is Parity Balance which is an even/odd balance cage sudoku. His showcase video provides an insight into how he sets puzzles and can be viewed by clicking the play button in the centre of the video above.
Selecting a sudoku title will allow you to play it, selecting Simon or Mark image next to the title will allow you to watch it.
