A game
You embed a game next to the explanations of the concept, and a student comes to try it.
The class takes part instead of watching you.
A game, a web page or an interactive document, usable in class without leaving your board.

You embed a game next to the explanations of the concept, and a student comes to try it.
checkThe class takes part instead of watching you.
You show a timeline or an online quiz, and the class goes through it with you.
checkEveryone follows on the same screen.

Simulation by PhET Interactive Simulations, University of Colorado Boulder, licensed under CC BY 4.0.