A "Rock - (Fill-in-the-Blank)".

No, not a rock garden.  Nope.  Not a rock 'n' roll song.  Nuh-uh.  Not the beginnings of a stone massage for mama.  A rock train, you say?  Why, yes!  That's it!  This is a rock train! Beneath our patio steps, we have what many small children covet:  rocks.  Big ones.  Small ones.  Flat ones. Bumpy ones. Gravely ones.  You name it, we have it.  

A. is constantly playing with the rocks, asking to bring them indoors (occasionally we let her and, frankly, I'm tired of finding stones all over the house. Seriously, they're everywhere).  She even refused to let go of one particular rock just before bedtime, ultimately falling asleep with it in her hand.  Yes, a child and her rock.  Or, in this case, rocks.  A child and her train of rocks.  And who needs store-bought toys?  Yeah, not us.