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 man digging a hole, the other 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 in to 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 his brow and sighed, 'Well, I suppose it probably looks odd because we're normally a three-person team. But today the lad who plants the trees called in sick.'