If you've ever wondered how neural networks work behind the scenes, check out this guide to implementing neural networks in scratch with R, by David Selby. You may be surprised how with just a little linear algebra and a few R functions, you can train a function that classifies the red dots from the blue dots in a complex pattern like this:
David also includes some elegant R code that implements neural networks using R6 classes. For a similar implementation using base R function, you may also want to check out this guide to implementing neural networks in R by Ilia Karmanov.
Tea & Stats: Building a neural network from scratch in R