Interesting metaphor! At the start of complex projects all you first see is sand. With every question you brush away a layer of sand and slowly but steadily you start seeing objects. The deeper you dig the better you see the objects. But digging deep is not enough, you also have to dig in a wide range to make sure you have found all the objects that are there to be found. You start seeing the connection between the objects too. It took a moment before this metaphor sunk in after reading your article. :)