My triangles are all messed up. Then the mistake boiled down to this piece of code

//6. bottom-triangles
//b1, b4, f3
1,-1,1,		-1,-1,1		-1,-1,0,
//b1, f3, f4
1,-1,1,		-1,-1,0,	1,-1,0

Compiler is fine. Just my triangle! Can you spot the mistake! it is a fun mistake.

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