创建半坡屋顶(Half-hip)。
roofHalfHip(height, hipHeight)
attr x = roofHalfHip(height, hipHeight)
@StartRule
Lot --> primitiveCube(6, 4, 6)
extrude(5)
comp(f) { top: Roof | side: Wall }
Roof --> roofHalfHip(30)
color(0.5, 0.25, 0.15)
Wall --> color(0.75, 0.72, 0.68)