The Window

I have a window and it's a small one.  There is a window of opportunity to put my daughter down for a nap.  If I jump at the first signs that she's tired and all the stars are in alignment that I can usually put her down without too much trouble.  Although, if the dog barks, I rearrange myself, or breath than the little bugger poops right out of half asleep into hyper toddler mode.  How does she do that?  I mean she's tired, go to sleep already.  I saw my window close ten minutes ago.  The blinds were closed, the door was closed, her eyes were closing and her breathing was getting deeper.  Stupid mommy tried to reposition my leg that was falling asleep and the child is now wide awake.  Sigh!  Looks like another day either without a nap or a late nap.  I think I'll try again in 30 minutes.  Have you ever seen you're window closing?  What did you do to tried to get it back?