Losing my marbles

Not quite yet, in the metaphorical sense, but She has been fascinated by them since she was a small baby. I have a  considerable quantity, some dating from my own childhood but most collected by my sons and corralled by me into a  large glass jar that stands on the window sill. Most days she asks to play with them so naturally a few have escaped the tray and rolled under the furniture. When I say play she is of course learning about numbers, weights and colours, the sounds they make as they clash together and the way they roll, gather and reflect the light. 
Marble appreciation for the next generation.