myx<-runif(50,0,10)
 myeps <- rnorm(50,0,5)
 myy <- 0.1*myx + myeps

 mylm <- lm(myy~myx)
 plot(fitted(mylm),resid(mylm)); abline(h=0)
 windows()
 plot(myy,resid(mylm));abline(h=0)