"Federico is the ultimate shape-shifter, in a way," said MASS MoCA director Joseph C. Thompson in a statement. "The bricks and mullions and windows of our buildings become files of digital data; the pixels become black spheres meticulously cut, stacked and assembled; the courtyard becomes and contains sculpture. There's something alchemical or magical about it, and all the while Federico remains behind the curtain, as if to say, 'Look ma, no hands.'"
The math and data behind the structure seems a little fuzzy, but hey, that's a lot of balls. The construction is kind of cool too (video below).