Envy of the 3D modeling abilities of Hans, I have tried mine. So, new thread for string related plots. In this post, you can see interacting strings. Really you can not guess if each vertex is a fermion or a boson in a superstring theory; I can not see how to tell it in pictorial way. So even the closed string in the second picture could be a fermion, albeit it is not my intention. To me, the second picture is more as an electron with a photon in an electromagnetic 3-vertex Feynman diagram.