Dual code key information using images.
On a desktop, use MindMup (free).
On an iPad, use SimpeMind.
Dual code key events using a timeline.
Add images and event descriptions to your timeline.
This tutorial uses the freemium version of time.graphics but there are templates for Google Slides and Apple Pages available on the internet.
Dual code key information with a visual stimulus.
Use Apple Numbers as a large blank learning space/wall.
If you can't remember how to use Apple Numbers in this way, removing the spreadsheet from the space, follow this tutorial
Dual code linear processes using a flowchart.
Diagrams.net (formerly draw.io) is a Google product and part of our suite of Google Workspace for Education Tools.
Diagrams.net does much more than just flowcharts... take a look!