Calca: Text Editor + Math = "Literate Programming"

iOS app created in C# with Xamarin tools
In fact it was created on Mac, not on Windows!

Calca - The Text Editor that Loves Math


Podcast interview @ Hanselminutes

This is also an example of "Literate Programming"
"is an approach to programming introduced by Donald Knuth in which a program is given as an explanation of the program logic in a natural language, such as English, interspersed with snippets of macros and traditional source code, from which a compilable source code can be generated"

the same author previously created popular iCircuit, also in C#

code reuse from Mac to iOS