Two blond girls were working for the council works department. One
would dig a hole and the other would follow behind her and fill the hole
in.. They worked up one side of the street, then down the other, then
moved on to the next street, working furiously all day without rest, one
girl digging a hole, the other girl filling it in again.
An onlooker was amazed at their hard work, but couldn't understand what
they were doing. So he asked the hole digger, 'I'm impressed by the
effort you two are putting into your work, but I don't get it -- why do
you dig a hole, only to have your partner follow behind and fill it up
again?'
The hole digger wiped her brow and sighed, 'Well, I suppose it probably
looks odd because we're normally a three-person team. But today the
girl who plants the trees called in sick.