I am trying to make a random reduced Latin Square and it looks like the most efficient algorithm is the algorithm introduced by Jacobson and Matthews
M. T. Jacobson and P. Matthews, Generating uniformly distributed random Latin squares, J. Combinatorial Design 4 (1996): http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1520-6610(1996)4:6%3C405::AID-JCD3%3E3.0.CO;2-J/abstract;jsessionid=CD8E1B9E7531FB739C31F1A33A7BA1E1.f02t01?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+17th+December+2016+at+09%3A00+GMT%2F+04%3A00+EST%2F+17%3A00+SGT+for+4hrs+due+to+essential+maintenance.Apologies+for+the+inconvenience
in one part they introduce us to $\pm$-moves I don't understand what is $2 \times2\times2$ subcube how to determine if a cell is 0-cell or 1-cell 0r -1-cell;
can please someone explain this to me