I'm trying to explain this to myself and can only come up with either horizontally or vertically depending on how you think about it. e.g. if there's a mirror standing on the floor and I'm lying horizontally on the floor looking into the mirror, I can say my image is flipped left-right from my vantage point or vertically wrt. normal standing. But also that my sideways image is flipped head-to-toe, as in bilaterally in normal standing position.
Wow that’s a mindfuck. I understand it in an optical sense but not intuitively. Do you have a good explanation for this?
No. It’s a fucking nightmare. The only clue I can give myself is that if I were to stand on a mirrored floor and look down, then actually I would then be flipped vertically, but not horizontally. Although that just makes me more confused really.