Press the right key for the next slide (or swipe left)

also ...

Press the left key to go backwards (or swipe right)

Press n to toggle whether notes are shown (no equivalent if you don't have a keyboard)

Press m or double tap to see a menu of slides

 

Formal Counterexamples with zoxiy

Here is a video with sound which explains how to construct a possible situation both informally (by drawing it) and formally.

This video (with sound) explains how to construct a possible situation in which an identity statement is false, first informally and then formally.

Here you can see how to use zoxiy to create a possible situation in which a sentence involving quantifiers and predicates is true.

The trickiest task with possible situations is to construct a counterexample to an argument, as in this example.