Wolfram Demonstrations Project is a collection of over 11,000 interactive modules that illustrate a certain concept or formula. Unlike videos, the user can change parameters and see how the system reacts. This visual style of mathematics can aid in understanding the underlying structure of the formulas.

Firstly, you need to download the CDF Player. All the Demonstrations are saved as a Computable Document Format (CDF) file and can only be run within the CDF Player. In many ways, these are Mathematica applets. The CDF Player comes in at a hefty 1 GB, so may take a while to download, depending on your connection speed.
For content creators on Steemit, these CDF Demos can be linked to within articles on the same topic. The reader can thereby test out ideas and interact with the software, rather than just seeing images and videos.
All CDF files are open source, so you can even adapt an existing demo or write your own from scratch.
Go to the Wolfram Demonstrations Project.