(adsbygoogle = window.adsbygoogle || []).push({ google_ad_client: "ca-pub-9528292055341919", enable_page_level_ads: true }); Have you ever counted the steps while you were going up and down your stairs?  Or, maybe you know exactly on which step your stairs creak. This is how I know that there are 15 steps in our staircase and where not to step to avoid a creak.  I know there must be more folks like me who know their stairs so well from climbing up and down, up and