Lego??

Little boxes on the hillside,
Little boxes made of ticky-tacky,
Little boxes, little boxes,
Little boxes, all the same.
There's a green one and a pink one
And a blue one and a yellow one
And they're all made out of ticky-tacky
And they all look just the same.

Ok, so not quite lego, but my children are faaarrr too old for lego these days.
I don't even have those odd single bricks that hang around for years, just waiting for a bare foot to land on them.