Sort:  

Yup I know that one. In the post I also refer to a video which presents the pi=4 "proof". :o)

The link you gave also does not pinpoint the problem :P

No it doesn't, however I have seen the proper solution (which points out the problem) a few times.

However the page has a few more problems, like the ones you discuss, which is why the link is a little better than just dropping an image.

So far I have only seen the wrong reason. Although this is a nice video

The explanation is incomplete.

The suggested reason in this video is also incomplete (she is not very clear in saying if she is anwering the question or not)

I am pretty sure somebody out there must have a written nice explanation for it. But it most likely drowned in incorrect/incomplete answers