#4.2.3 Ice cream Flavour Example
x<-matrix(c(
2,	1,	NA,	3,	NA,	NA,	NA,
NA,	2,	3,	NA,	1,	NA,	NA,
NA,	NA,	1,	2,	NA,	3,	NA,
NA,	NA,	NA,	1,	3,	NA,	2,
2,	NA,	NA,	NA,	1,	3,	NA,
NA,	1,	NA,	NA,	NA,	2,	3,
1,	NA,	3,	NA,	NA,	NA,	2,
NA,	NA,	3,	1,	NA,	2,	NA,
NA,	NA,	NA,	2,	1,	NA,	3,
2,	NA,	NA,	NA,	1,	3,	NA,
NA,	1,	NA,	NA,	NA,	3,	2,
1,	NA,	2,	NA,	NA,	NA,	3,
1,	3,	NA,	2,	NA,	NA,	NA,
NA,	2,	3,	NA,	1,	NA,	NA),ncol=7,byrow=T)
colnames(x)<-c("A","B","C","D","E","F","G")

xtotab(x)
U(x)
BlockAnalysis(x)