Squares > 5x5 may take rather long if you have Netscape 2, a 386, or limited memory.
Did you know that there are 161,280 different possible 5 x 5 Latin squares!
(don't believe me?) then see:
Cooper, B.E. 1969. Statistics for Experimentalists. Pergamon Press, London.
Federer, W.T. 1955. Experimental Design. MacMillan Co., New York.
BASIC code and discussion of Latin squares
BASIC code for Latin squares modified from that in:
Byers, J.A. 1996. Random selection algorithms for spatial and temporal
sampling. Computers in Biology and Medicine 26:41-52.
other related programs:
Byers, J.A. 1991. BASIC algorithms for random sampling and treatment
randomization. Computers in Biology and Medicine 21:69-77.
Byers, J.A. 1993. Randomization algorithms in BASIC for experimental
design. Computers in Biology and Medicine 23:167-176.