Scatter Plot Smoothing

y <- cars$dist
x <- 1:length(y)
plot(x, y, pch = 20)
lines(lowess(y~x, f = 0.9), col="green", lwd=2)
lines(lowess(y~x, f = 0.5), col="blue", lwd=2)
lines(lowess(y~x, f = 0.1), col="red", lwd=2)

Details: https://youtu.be/zPafVva9BwE