BB pal Eric Paulos points to this ingenious design for a billboard that uses the sun to transform what the viewer sees. From the Cannes Lions Archive of international ads:
The billboard is made of 12,148 aluminium pegs, varying in length from 1mm to 27mm. Each different length peg creates a different sized shadow. The different sized shadows create a greyscale image of a woman sunbathing, when the sun comes out.
UPDATE: Eric Paulos adds that the billboard technique is similar to Christian Moeller's "dePictured (Bitwall 4)" artwork. Link
