A ball plays the sound as it goes down unsteadily, it falls off sometimes. But the movement we can’t help cheering up seems some how like our lives. It fails sometimes. And it could go straight down without swaying if the adjustment was determined that way. But we like adjusting it purposely with an unstable way. It is alright to have a stable life but we prefer to go sometimes too far, making mistakes and living with challenges. You may find the xylophone showing who did the adjustment of it.