 The fountains use over one million LEDs . The inner surface of each tower uses 147 smaller screens with a total of 264 @,@ 480 LED points ( each with two red , one blue and two green LEDs ) . The physical demands of LED screens , in particular the red , green , and blue long @-@ life light bulbs and the requisite circuitry , created three major challenges : supporting the physical structure , combating heat buildup , and optimizing perceptibility of the display . Plensa had used LED fixtures on previous projects , and thus had some experience with these issues . The LED structure is not supported as a single wall ( which would be 50 feet ( 15 m ) high ) , but rather as several segments that are noticeable as visible horizontal bands every few feet : these show where the LED equipment is supported . The heat generated is handled by fans that cool the air at the bottom , that then works its way through the chimney @-@ like tower . Perceptibility was determined to be optimal with LED lights 2 inches ( 51 mm ) behind the glass . 
 The fountains use over one million LEDs . The inner surface of each tower <a href='uninflect' title='1'><mark>uses</mark></a> 147 smaller screens with a total of 264 @,@ 480 LED points ( each with two red , one blue and two green LEDs ) . The physical demands of LED screens , in particular the red , green , and blue long @-@ life light bulbs and the requisite circuitry , created three major challenges : supporting the physical structure , combating heat buildup , and optimizing perceptibility of the display . Plensa <a href='been_done' title='2'><mark>had</mark></a> used LED fixtures on previous projects , and thus had some experience with these issues . The LED structure is not supported as a single wall ( which would be 50 feet ( 15 m ) high ) , but rather as several segments <a href='null_relcl' title='3'><mark>that</mark></a><a href='drop_aux' title='4'><mark>are</mark></a>noticeable as visible horizontal bands every few feet : these show where the LED equipment is supported . The heat generated is handled by fans <a href='null_relcl' title='5'><mark>that</mark></a>cool the air at the bottom , that then <a href='uninflect' title='6'><mark>works</mark></a> its way through the chimney @-@ like tower . Perceptibility was determined to be optimal with LED lights 2 inches ( 51 mm ) behind the glass . 
The fountains use over one million LEDs . da inner surface of each tower use 147 smaller screens wid a total of 264 @,@ 480 LED points ( each with two red , one blue and 2 green LEDs ) . Tdaphysical demands of LED screens , in particular thdaed , green , and blue long @-@ life light bulbs and thedaquisite circuitry , created three major challenges : supporting the physical structure , combating heat buildup , and optimizing perceptibility of the daplay . Plensa done used LED fixtures on previous projects , and thus had some experience wwitthese issues . The LED structure ain't supported as a single wall ( which would b 50 feet ( 15 m ) high ) , but rather as several segments noticeable as visible horizontal bands every few feet : these show where the LED equipment is supported . The heat generated is handled by fans cool the adaat the bodam , dat then wrk its way through the chiday @-@ like tower . Perceptibility was determined to be optimal with LED lights 2 inches ( 51 mm ) behind the glass .