Presentations with Markdown, Pandoc, Impress.

 PAMPI is a free software to create presentations easily.
 .
 presentations are written in text files,
   - so they can be modified easily
   - the files syntax (Markdown) is easily learnt
   - many examples of usable Markdown are available at
     https://enacit1.epfl.ch/markdown-pandoc
  They are converted to web pages (HTML files)
   - one can view them with a browser
   - one can publish them online, grab them on a USB stick, etc.
 In PAMPI's interface, the Markdown file is displaied in the left
 side and on can view the result in the right side.
 .
 Every step of a presentation can be located in any position in a 3D
 space
   - one provides its coordinates
   - one can specify its zoom factor
   - one can specify rotations
 Maths can be authored with KaTeX.
 .
 Here are many examples: https://en.wikibooks.org/wiki/LaTeX/Mathematics.