Why are letters reversed on some signs?

[rhxoehwhfh]

help! light question

List some situations where the letters on signs are reversed. Explain why it is being done.

I have no clue T.T... can anyone help me with this question please?...

 

[rhxoehwhfh]

can anyone help me please..

 

[tyco05]

where have you seen letters printed in reverse before?

 

[Dick]

ecnalubmA. Sorry, couldn't resist.