The game of tic tac toe is not useful for every medical situation. This paper makes that clear:
“Tic-tac-toe does not provide lessons for appreciating the HLA–rheumatoid arthritis relationship: Comment on the editorial by Bridges et al.,” A.H.M. van der Helm-van Mil, T. W. J. Huizinga, R.R.P. de Vries, and R.E.M. Toes, Arthritis and Rheumatism, vol. 58, no. 11, 2008, p. 3635.