Add more MathML examples (#18654)

* Add more MathML examples

* fix internal links

* Update files/en-us/web/mathml/examples/index.md

Co-authored-by: Jean-Yves Perrier <jypenator@gmail.com>

* reword sentences

Co-authored-by: Jean-Yves Perrier <jypenator@gmail.com>

files/en-us/web/mathml/examples/index.md

@@ -6,9 +6,13 @@ tags:
   - Example
   - Guide
   - MathML
-  - NeedsBeginnerUpdate
 ---
-Below you'll find some examples you can look at to help you to understand how to use MathML to display increasingly complex mathematical concepts in Web content.
+
+Below you'll find some examples you can look at to help you to understand how to use MathML.
+
+## MathML formulas
+
+The following demos display increasingly complex mathematical concepts in Web content.
 
 - [Pythagorean Theorem](/en-US/docs/Web/MathML/Examples/MathML_Pythagorean_Theorem)
   - : Small example showing a proof of the Pythagorean Theorem.
@@ -18,3 +22,22 @@ Below you'll find some examples you can look at to help you to understand how to
   - : Original test from the Mozilla MathML project. It contains examples from the [TeXbook](https://en.wikipedia.org/wiki/Computers_and_Typesetting) with image references generated by TeX.
 - [MathML Browser Test](http://eyeasme.com/Joe/MathML/MathML_browser_test.html )
   - : A similar test with concrete formulas taken from Wikipedia.
+
+## Other Web technologies
+
+The following demos mix MathML with other Web technologies to produce advanced content.
+
+- [`<la-tex>` custom element](https://fred-wang.github.io/TeXZilla/examples/customElement.html)
+  - : A [custom element](/en-US/docs/Web/Web_Components/Using_custom_elements) that accepts [LaTeX](https://en.wikipedia.org/wiki/LaTeX) content.
+
+- [Magnetic field demo](https://fred-wang.github.io/TeXZilla/examples/toImageWebGL.html)
+  - : A 3D representation of a magnetic field, using [SVG](/en-US/docs/Web/SVG) and [WebGL](/en-US/docs/Web/API/WebGL_API).
+
+- [Συνάρτηση ζήτα Ρήμαν (el)](https://fred-wang.github.io/MathFonts/%CE%A3%CF%85%CE%BD%CE%AC%CF%81%CF%84%CE%B7%CF%83%CE%B7_%CE%B6%CE%AE%CF%84%CE%B1_%CE%A1%CE%AE%CE%BC%CE%B1%CE%BD.html)
+  - : A greek article about the Riemann zeta function, with [Web fonts](/en-US/docs/Learn/CSS/Styling_text/Web_fonts) from the [Greek Font Society](https://greekfontsociety-gfs.gr/).
+
+- [Pell's equation](https://people.igalia.com/fwang/pell-bigint-mathml/)
+  - : A JavaScript program to solve Pell's equation using [`BigInt`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt).
+
+- [Lovelace's program for Bernouilli numbers](https://people.igalia.com/fwang/lovelace-jsclass-mathml/)
+  - : An emulator for Ada Lovelace's program to calculate Bernouilli numbers, using [Private class features](/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields).