▁with ▁two ▁o ak ▁trees ▁plant ed ▁in ▁the ▁middle ▁alongside ▁art ▁install ations ▁designed ▁by ▁the ▁sculpt ors ▁Steven ▁G ont ar ski ▁and ▁Reb e cca ▁Warren . ▁ ▁The ▁treatment ▁of ▁the ▁upper ▁flo ors ▁provides ▁a ▁striking ▁contrast . ▁ 1 3 4 , 0 0 0 ▁green , ▁orange , ▁l ime ▁and ▁yellow ▁gla zed ▁ter rac otta ▁t iles ▁cover ▁the ▁fa ç ades ▁in ▁ 1 3 ▁irregular ly ▁orient ed ▁vertical ▁pan els ▁on ▁the ▁external ▁per imeter . ▁The ▁fa ç ades ▁facing ▁the ▁inner ▁cour ty ard ▁are ▁l ined ▁with ▁another ▁eight ▁pan els ▁covered ▁with ▁grey ▁t iles , ▁a ▁design ▁which ▁project ▁architect ▁Maur its ▁van ▁der ▁Sta ay ▁says ▁was ▁intended ▁to ▁" ensure ▁that ▁the ▁upper ▁store ys ▁did ▁not ▁det ract ▁from ▁the ▁trans par ency ▁of ▁the ▁ground ▁floor ▁and ▁to ▁maxim ise ▁the ▁amount ▁of ▁light ▁reflected ▁back ▁into ▁the ▁offices ." ▁The ▁fa ç ades ▁are ▁hung ▁on ▁an ▁internal ▁ch ass is ▁car rier ▁system ▁( a ▁similar ▁system ▁is ▁in ▁use ▁in ▁another ▁P iano ▁development ▁on ▁Berlin ' s ▁P ots d amer ▁Platz ). ▁Pier ced ▁by ▁rows ▁of ▁identical ▁windows ▁repeated ▁across ▁the ▁entire ▁development , ▁the ▁fa ç ades ▁are ▁expected ▁to ▁be ▁effectively ▁self - clean ing ▁and ▁imm une ▁to ▁f ading . ▁The ▁colours ▁of ▁the ▁fa ç ades ▁are ▁ev oked ▁in ▁the ▁design ▁of ▁many ▁of ▁the ▁development ' s ▁interior ▁f