Here we will quickly go though the basics of those two.

This notebook delves into quantum mechanics with a focus on symbolic quantum operators and spin-Hamiltonians. It begins with setting up orthogonality rules and defining the linear properties of basis functions.

Next, we investigate the spin-Hamiltonian for a cubic system with doubly degenerated orbital states, particularly focusing on $Fe^{2+}$ ions in cubic spinels with $^5E_g$ states. The Hamiltonian for a paramagnetic state is presented and implemented in code, followed by defining basis vectors and functions to find eigenvalues and eigenvectors, and calculating thermal averages of quantum operators.

MatrixPlot[
 Fourier[Table[
   UnitStep[i, 4 - i] UnitStep[j, 7 - j], {i, -25, 25}, {j, -25, 
    25}]]]

It means, MatrixPlot as well as Rasterize can work properly finally

There is nothing more exciting in programming than designing a graphics application. Thankfully, there is one person on Github Garrett Johnson, who implemented a path-tracing algorithm on top of the well-known THREE.js graphics engine. Moreover, it fully supports features from the original library and can be anytime flipped as a main renderer.