# Learning diff

mat <- read.table( text=
"TRUE  TRUE  TRUE
FALSE  TRUE  TRUE
TRUE  TRUE  TRUE
TRUE  TRUE FALSE
TRUE  TRUE FALSE
TRUE FALSE FALSE
TRUE FALSE FALSE")

mat <- as.logical(unlist(mat))
dim(mat) <- c(7, 3)
diff(mat)

> mat                       > diff(mat)
      [,1]  [,2]  [,3]           [,1] [,2] [,3]
[1,]  TRUE  TRUE  TRUE      
[2,] FALSE  TRUE  TRUE      [1,]   -1    0    0
[3,]  TRUE  TRUE  TRUE      [2,]    1    0    0
[4,]  TRUE  TRUE FALSE      [3,]    0    0   -1
[5,]  TRUE  TRUE FALSE      [4,]    0    0    0
[6,]  TRUE FALSE FALSE      [5,]    0   -1    0
[7,]  TRUE FALSE FALSE      [6,]    0    0    0


It looks like `diff` performs row-wise diffs. 
Row(2) - Row(1)    or Row("J") - Row("J-1")