Loved the simple concept in this poster. The eye drifts naturally downward into the shadow of the Legos. A great ad that symbolizes the imagination that Legos foster. Best of all it conveys this this with absolutely no text. Its all about IDEA!
This element of design is Negative Space. The hand isn't actually holding anything. It implies that there is a light bulb in the empty space. Negative space guides your imagination to finish the image.