TITLE: What book or website has nice, colorful diagrams illustrating real quadratic integer rings?
QUESTION [5 upvotes]: I'm sure you all have seen diagrams, colorful or not, illustrating prime numbers in $\mathbb{Z}[i]$ and $\mathbb{Z}[\omega]$, with some of them helpfully pointing out the inert and splitting primes from $\mathbb{Z}$. It seems fairly easy to make diagrams for other imaginary quadratic rings with unique factorization.
But for real rings like $\mathbb{Z}[\sqrt{2}]$ and $\mathbb{Z}[\sqrt{3}]$ there seems to be nothing. I've read some books that do mention real rings and have diagrams of imaginary rings have no diagrams for real rings. If there are no books with such diagrams, is there at least some website with such diagrams?

REPLY [2 votes]: Most number theory textbooks I read are algebraic in nature.  They are not that visual - except possibly for geometry of numbers - and are no pictures.
With programs like SAGE, it's possible to use computers to feel out number theory concepts, but it's still not common to try to visualize them.  Here I try to show that $\mathbb{Z}[\frac{1+ \sqrt{3}}{2}]$ is Euclidean

I have tried to visualize why certain rings are Euclidean made some progress in this math.SE response Prove that $\mathcal{O}_3$ and $\mathcal{O}_7$ are euclidean domains 
That answer is also my attempt to understand Curtis McMullen's talk Lattice Stars and Arithmetic Chaos