na
Nope, thats not how its working! You’re connecting the vertices of the first generated box all over again.
Create Mesh Section - Triangles: Index buffer indicating which vertices make up each triangle. Length must be a multiple of 3.
So its always
1-2-3-1-2-3-1-2-3 | Because you’re adding the same indexes all over again in Temp Room Triangles, without thinking about the old ones
it should be
1-2-3-4-5-6-7-8-9 | You have to connect it with the correct vertices index.
Not sure though, but my thought on it.
Should be fixed if you add the correct vertice index
X * Y * Array Element (Triangle) instead of Array Element (Triangle) to the Temp Room Triangles.
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Took me some time to figure it out though. Hope it works 
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Got it. Took me some time to find the error. We had to use the amount of vertices of course. The Array Element points to the vertice index, not the triangle index. (Stupid mistake 
)
Got 2 solutions:
First one as you had planned with 1 section. (Sorry for the mess, didn’t clean up. Branch is useless though.)
Second one with more sections. (temp count default value is -1! | and the branch is useless though, didn’t delete it.)
Have fun. 
edit: Please note that the “unseen” triangles between the blocks are still there.
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