Author: Urs Format: MarkdownItexmentioned the concept of lifting in a square and added the diagrams illustrating the situation
<a href="https://ncatlab.org/nlab/revision/diff/lift/2">diff</a>, <a href="https://ncatlab.org/nlab/revision/lift/2">v2</a>, <a href="https://ncatlab.org/nlab/show/lift">current</a>
mentioned the concept of lifting in a square and added the diagrams illustrating the situation