Draw multiple triangles from a 2d vector of dots C#

I'm trying to draw multiple triangles (2D) from a 2d array that changes every frame. The 2d array holds an unknown amount of 3 Vector3s. Here is what I've tried so far:

 void Update()
 {
         foreach (Vector3[] triangle in triangles)
         {
             Mesh mesh = new Mesh();
             mesh.Clear()
             mesh.vertices = triangle;
             mesh.triangles = new int[] { 0, 1, 2 };
             GetComponent<MeshFilter>().mesh = mesh;
         }
 }

but it doesn't seem to work how I wanted.