The Chinese character
means ‘good luck’
and when placed upside-down (fig.)
as here, it is used to invite good luck
to come, since the last two characters of dao guo lai (倒过来), which means
‘upside-down’, are the same (过来) as those used to say ‘to come over’
or ‘to come up’. It is also often posted upside-down on the front door of
a house or an apartment (fig.).
It is used much the same as the law of attraction, hoping that by
posting it in this way, it will in fact attract good luck.