https://www.youtube.com/watch?v=sXttZFipmvM
roof
https://www.youtube.com/watch?v=rmE69N46ONI
https://www.youtube.com/watch?v=v6qsBeTV3zI
https://www.youtube.com/watch?v=E1-DJVcsI6c
https://www.youtube.com/watch?v=n2EjeW4-Qx4
https://www.youtube.com/watch?v=Aa2XVNCX0PU