```
par(mfrow=c(1,2))
Canvas()
DrawEllipse(rot = c(1:3) * pi/3, col=SetAlpha(c("blue","red","green"), 0.5) )
plot(cars)
m <- var(cars)
eig <- eigen(m)
eig.val <- sqrt(eig$values)
eig.vec <- eig$vectors
DrawEllipse(x=mean(cars$speed), y=mean(cars$dist), radius.x=eig.val[1] , radius.y=eig.val[2]
, rot=acos(eig.vec[1,1]), border="blue", lwd=3)
```

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