This function just fulfills a very naive idea about moving window regression
using rectangles to denote the `windows`

and move them, and the
corresponding AR(1) coefficients as long as rough confidence intervals are
computed for data points inside the `windows`

during the process of moving.

The AR(1) coefficients are computed by `arima`

.

```
library(animation)
## moving window along a sin curve
ani.options(interval = 0.1, nmax = 50)
par(mar = c(2, 3, 1, 0.5), mgp = c(1.5, 0.5, 0))
mwar.ani(lty.rect = 3, pch = 21, col = "red", bg = "yellow", type = "o")
```

plot of chunk demo-a

```
## for the data 'pageview'
mwar.ani(pageview$visits, k = 30)
```

plot of chunk demo-b