why do mirrors reverse left and right but not up and down?
thank you very much.
Mirrors do not reverse up-down nor left-right. Your (up) head is always up and your right hand is always at right.
What a mirror reverse is front-back. If you are heading North, your image is heading south.
A mirror can reflect 'upside down'---it just depends on the angle of reflection.
From the Usenet Physics FAQ:
I'm wondering who the hell Trimotio and Fineas are. Like Alice and Bob, or are they random names, or what?
I thought they were the 1/2 wave virtual non-local representative ghost MWI counter-equivalents of Bob and Alice.
Separate names with a comma.