 The glass was custom @-@ made at a factory in Mount Pleasant , Pennsylvania , and shipped to the structural glass panel manufacturer in Melbourne , Florida . The panels were then shipped by truck to Chicago . The glass is white glass , rather than the usual green glass that results from iron impurities . This has the tradeoff of increased image clarity , but greater dirt visibility . Each block is 5 by 10 by 2 inches ( 127 by 254 by 51 mm ) with glass thin enough to avoid image distortion . On each block , one of the six faces is polished , and the other five surfaces are textured . 
 The glass was custom @-@ made at a factory in Mount Pleasant , Pennsylvania , and shipped to the structural glass panel manufacturer in Melbourne , Florida . The panels <a href='uninflect' title='1'><mark>were</mark></a> then shipped by truck to Chicago . The glass <a href='drop_aux' title='2'><mark>is</mark></a>white glass , rather than the usual green glass <a href='null_relcl' title='3'><mark>that</mark></a><a href='uninflect' title='4'><mark>results</mark></a> from iron impurities . This <a href='got' title='5'><mark>has</mark></a> the tradeoff of increased image clarity , but greater dirt visibility . Each block <a href='drop_aux' title='6'><mark>is</mark></a>5 by 10 by 2 inches ( 127 by 254 by 51 mm ) with glass thin enough to avoid image distortion . On each block , one of the six faces is polished , and the other five surfaces are textured . 
The glass was custom @-@ made at a factory in Mount Pleasant , Pennsylvania , and shipped to da structural glass panel manufacturer in Melbourne , Florida . The panels was then shipped by truck to Chicago . Tdaglass white glass , rather den the usual green glass result from iron impurities . This got thdaradeoff of increased image clarity , but greater dirt visibility . Each block 5 by 10 by 2 inches ( 127 by 254 by 51 mm ) with glass thin enough to avoid image distortion . On each block , one of the six faces is polished , and thedaher five surfaces are textured .