WT40: The fundamental theorem of projective geometry

[MrFunatabi]

In the diagram that was explained around 5:00, if I exchange B" and C", it seems I need an extra line through A'' for another intermediate perspectivity. Is there a way to do it in less steps?

[jakbarzel]

thank you, these videos are very helpful .

[786HKHM]

Thanks you. I think this one more time to get it.