A polygon uses the same vertex twice error in animation nodes

In the documentation it shows earlier version of animation nodes which didn’t require you to add the edges to create a mesh. In v2.1, if you want to remove any errors make sure you add the vertices then edge indices then polygon. I don’t think you need a maths node, you just need to connect your edge indices from the original mesh info straight to your Combine Mesh Node and everything should work.

I fixed it by connecting the math add node to index instead of iterations and added the edges of polygons node.