Creating a triangle

[thick owl]

It's a simple yet seeming impossible task and i don't see any answers on how to create a 2d triangle for my model
I'm trying to create a elbow pipe but in order to do the curve i would need triangles.

[vague tree]

You can't really, only cubes are supported in the Bedrock format
You can try faking it with an erased plane with a higher resolution