Lily tried now to clamber up on her father's desk. If he came back and she was lying on his papers, he very well couldn't work and then they could play some more. As her tiny body scaled Harry's swivel chair, her hand accidentally pushed out as she tried to get a grip on the polished wood, pushing her away from the desk. The desk chair ran into something - Daddy's Pensieve. Lily knew she wasn't ever supposed to touch it, and usually it was locked, in Daddy's closet, but he had needed to use it in order to help place his business call.