By Clive Groome
By ApSimon, Hugh
By Kirkby, David
By Tyler, Jenny, Round, Graham
By Wilson, Robin
By Straker, Anita
By Weinberg, Steven
By Fogle, Ben
By Michael Holt and Zoltan Dienes
By Pinel, Adrian, Pinel, Jeni
By Noaa, N/A
By Gardner, Martin
By Devadas, Srini
By Haselbauer, Nathan
By Dunn, Angela Fox
By Jenny Tyler, Graham Round
By Sachar, Louis
By Bartlett, Roger
By Matthew Syed
By Taylor, Don
By Mullins, Roy
By Jenkins, Adrian
By Phillips, Richard
By Sole, Puzzles Numbers and Infinity Tim
By Bloom, Jonathan
By Shasha, Dennis E.
By Cadwell, J. H.