I think that 8 might be possible, by interlocking two Star Trek symbols as shown below. 

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/RyurZ.png

**Adendum:** This candidate may not work, as quarague points out, but  I leave it as a potential "how not to" example. There are other ways to cross the two figures, while they remain unlinked, and one of these variations could be more promising.