Problem with Graphmapper

I’ve been following this youtube tutorial and for some reason I’m getting the opposite result from what I want lol. Rhino Grasshopper Tutorial Parametric Facade - YouTube

I want the panel to look like there’s some force pulling it in the parts when the facade is not touching the ground (first image) and the result I’m getting is the second image.

Not sure where I made the mistake and I tried reversing it in several moments but so far nothing. If anyone could help me it would be much appreciated.
r00_Fachada (35.0 KB)

in the description of the youtube video there’s a link from which you can download the very same GH file defined along the video