#21: Antinoise window boxes

For people unable to fit double glazing (due eg to building regulations) window boxes could be filled with artificial plants.

These would have a range of stem lengths tuned to absorb the low frequency techno-funk that drives me nuts.

Alternatively, the stalks could be automatically shortened or lengthened and actively wafted about in order to cancel whatever offensive noise young Barry has taken it into his baseball-capped head to create outside my window.