```
x <- c(1, 3, 6, 7)
Midx(x)
Midx(x, incl.zero = TRUE)
Midx(x, incl.zero = TRUE, cumulate = TRUE)
# an alternative to
head(MoveAvg(c(0, x), order = 2, align = "l"), n = -1)
tab <- matrix(c(401,216,221,254,259,169), nrow=2, byrow=TRUE)
b <- barplot(tab, beside = FALSE, horiz=TRUE)
x <- t(apply(tab, 2, Midx, incl.zero=TRUE, cumulate=TRUE))
text(tab, x=x, y=b, col="red")
```

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