s ▁rot or el ief s . ▁These ▁are ▁designs ▁painted ▁on ▁flat ▁card board ▁circles , ▁which ▁are ▁ ▁to ▁be ▁sp un ▁on ▁a ▁ph on ographic ▁tur nt able . ▁The ▁work ▁was ▁later ▁ch ore ograph ed ▁by ▁Mer ce ▁C unning ham . ▁The ▁global ▁structure ▁is ▁ 1 1 x 1 1 ▁( ele ven ▁sections ▁of ▁eleven ▁bars ▁each ), ▁the ▁rh yth mic ▁proportion ▁is ▁ 2 , ▁ 1 , ▁ 1 , ▁ 3 , ▁ 1 , ▁ 2 , ▁ 1 . ▁Similarly ▁to ▁T oss ed ▁As ▁It ▁Is ▁Un tr ouble d ▁and ▁The ▁Un available ▁Memory ▁of , ▁the ▁work ▁mostly ▁builds ▁on ▁a ▁single ▁mel od ic ▁line , ▁which ▁uses ▁notes ▁m uted ▁by ▁weather ▁stri ppings . ▁This ▁piece ▁is ▁one ▁of ▁the ▁first ▁to ▁explore ▁the ▁idea ▁of ▁silence ▁system atically : ▁empty ▁bars ▁are ▁ju xt ap osed ▁with ▁mel od ic ▁pass ages ▁throughout ▁the ▁piece . ▁ ▁Son at as ▁and ▁Inter l udes ▁▁ ▁A ▁cycle ▁of ▁ 2 0 ▁short ▁works ▁( 1 6 ▁son at as ▁and ▁ 4 ▁inter l udes ) ▁composed ▁in ▁ 1 9 4 6 – 4 8 . ▁ ▁D edic ated ▁to ▁pian ist ▁Mar o ▁A jem ian . ▁This ▁is ▁C age ' s ▁most ▁famous ▁work ▁for ▁prepared ▁piano , ▁and ▁also ▁the ▁most ▁complex : ▁piano ▁prepar ation ▁takes ▁about ▁ 2 – 3 ▁hours ▁and ▁involves