Not exactly . For example i have 10 sprites with instance variable "ID" 0 to 9 and second instance variable "NUM" random 1 to 4 . I have a random number "n" start 0 until 9 and a second number "NUM2" random 1 to 4 . If "n" has value 3 for example i ll must check in the list of sprites the n+1, n+2 or n-1, n-2 so it will be sprites with ID 4,5 or 2,1 . After with the number "NUM2" i must compare instance variable "NUM" of sprite 4,5 or 2,1 and if is equal i destroy sprites with ID 4,5 or 2,1 and to finish i reorder the list of id like you say