The structure for the blocks was a challenge . At first , the design team had considered switching to plastic blocks , until the team found Circle Redmont Inc . , a prefabricated glass panel company in Melbourne , Florida which specialize in structural glass panel systems . Circle Redmont came up with the plan of turning grates on their sides to be used as building elements . The individual grids are 5 feet ( 1 @.@ 5 m ) tall and either 16 feet ( 4 @.@ 9 m ) or 23 feet ( 7 @.@ 0 m ) wide with cell capacity of an average of 250 blocks . Each tower is composed of 44 grids stacked and welded . The combination of the refraction of the glass and the thinness of the metal make the grid virtually invisible .