Kirchhoff's circuit laws - regular tetrahedron
Since this is homework, I'll rather &quot;hint&quot; you in the right direction to help you employ the right methods than solve it completely, I think you'll enjoy that more!
This gets doable if you start with your first schematic, and apply the Y-Delta transformation on the &quot;inner&quot; three R (those who connect to C). Afterwards, you will have two parallel triangles, and can d simplify the &quot;double edges&quot; individually.