According to the write-up I read early they put metal under the skate park surface.
www.wired.co.uk/news/archive/2015-06/24/lexus-hoverboard
( , Wed 24 Jun 2015, 16:23, Share, Reply)
www.wired.co.uk/news/archive/2015-06/24/lexus-hoverboard
( , Wed 24 Jun 2015, 16:23, Share, Reply)