SceneKit custom geometry

SceneKit custom geometry:

I know multi position(SCNVector).



how do I create the custom geometry.



the bottom side position:(0,0,0) (50,0,0) (50,0,-50) (150,0,-50) (150,0,125) (0,0,125) (25,0,75) (25,0,50) (0,0,50)



the top side position:(0,2,0) (50,2,0) (50,2,-50) (150,2,-50) (150,2,125) (0,2,125) (25,2,75) (25,2,50) (0,2,50), y—axis move 2

please help me ,Thanks

SceneKit custom geometry
 
 
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