Jenkins remains an engaging writer.  So far none of the commenters responded to the intent of the sign hanger, which was to spur discussion about that lot.  It may be grassy, but it's not halfway to being a park already.  I think you'll find that parcel has some toxics issues, so there'll have to be some cleanup before it's salable.  A park on that parcel would be hell to police, so maybe something else.  Maybe micro-apartments. Gentrify the 'hood with some poor, brave millennials?