Here is an article
https://medium.com/a-problem-like-maria/understanding-android-matrix-transformations-25e028f56dc7
In the Scaling paragraph it says (at the end) that
But you can do with scaling. The image around the axis (or two)
Also in the article there is an example of rotation around the axis and it looks as if it looks normal, but when you do it with a twist that is larger in size (say on the floor of the screen - some kind of container), you can see how all such scaling works, which seems to make flip, but still remains scaling.
So the question is how to make a real flip ?