Around The Library at Willesden

As we wait for the official opening of The Library at Willesden today, and the result of the Labour Leadership election, I notice that mush of the work around Willesden Library Centre is now complete.

Trees are now planted at the back walk way that opponents claimed would be a "Muggers' Alley":

The contractors appear to be finishing off the paving, and we must be close to the point when people can start using it either to access the Library or as a cut through between the bus stops on Harlesden Road and Brondesbury Park. 

On the Grange Road side, where work seems pretty much done, a "tuning stone" has appeared.  I have never heard of one of these before, but this is what it looks like:

This is what the plaque by the side says:

I imagine that these rather odd looking pipes near by must be linked to it.