' ▁edition ▁of ▁Bac chan ale ▁specified ▁ 1 9 4 0 ▁as ▁the ▁date , ▁and ▁this ▁has ▁been ▁used ▁by ▁numerous ▁sch ol ars ▁since . ▁The ▁circumstances ▁of ▁the ▁piece ' s ▁composition ▁are ▁much ▁more ▁clear : ▁it ▁was ▁created ▁for ▁a ▁ch ore ography ▁by ▁the ▁American ▁dan cer ▁Sy villa ▁Fort . ▁C age ▁and ▁Fort ▁were ▁both ▁working ▁at ▁the ▁Corn ish ▁School ▁in ▁Seattle , ▁Washington ▁at ▁the ▁time . ▁The ▁room ▁where ▁the ▁dance ▁was ▁to ▁be ▁performed ▁was ▁not ▁large ▁enough ▁to ▁allow ▁for ▁a ▁per cussion ▁ensemble , ▁but ▁had ▁enough ▁space ▁for ▁a ▁grand ▁piano . ▁C age ▁decided ▁to ▁try ▁placing ▁various ▁objects ▁on ▁the ▁strings ▁of ▁the ▁instrument ▁in ▁order ▁to ▁produce ▁per cuss ive ▁sounds , ▁inspired ▁by ▁Henry ▁Cow ell ' s ▁experiments ▁with ▁extended ▁piano ▁techniques . ▁In ▁ 1 9 8 2 ▁C age ▁mentioned ▁that ▁the ▁whole ▁piece ▁was ▁completed ▁in ▁just ▁three ▁days . ▁Tw elve ▁notes ▁are ▁prepared , ▁mostly ▁using ▁weather ▁stri ppings . ▁In ▁the ▁score , ▁in ▁ 1 1 ▁cases ▁out ▁of ▁ 1 2 , ▁the ▁perform er ▁is ▁instruct ed ▁to ▁" det erm ine ▁position ▁and ▁size ▁of ▁m utes ▁by ▁experiment ." ▁ ▁Tot em ▁An c est or ▁ ▁Com posed ▁in ▁ 1 9 4 2 ▁for ▁a ▁dance ▁by ▁Mer ce ▁C unning ham . ▁ ▁Ele ven ▁notes ▁are ▁prepared , ▁eight ▁of ▁them ▁by ▁sc rew s . ▁This