|Triax is 3 layers of uni knitted​ together with fine polyesyer thread.
|Double bias and biax are 2 layers knitted together. Uni is one layer,
|knitted to keep the fibres aligned. Triax is hard to get around tight
|corners, but on flat surfaces it is little or no different to 3 layers
|of
|uni or one of biax/double bias with a layer of uni on top.

Once again, I defer. I was thinking something like this.
https://www.jamestowndistributors.com/userportal/show_product.do?pid=97449
Where the threads are woven, thus pulled out of plane.

I have not seen stitched together uni triax.