This XLSX toolbox allows the user to create XLSX files with numbers, equations and layout.
How it works :
A Microsoft Excel Open XML Format Spreadsheet is just a zip archive with .XML files.
This software first decompresses (unzip) an empty XLSX file to a temporary folder. Then it writes the data and layout from the user to the XML files. Finally it compresses the folder to a zip-archive and renames it to wanted XLSX filename.

The toolbox is still in development, please look in "example.m" to see how the code is used.