Answer:
Cubane, C8H8
It "sorta" looks like this.
....H.........H
......\......../
H.....C - C
...\../.|.../.|
....C - C.C- H
.... |.....|./
....C - C
.../.........\
H............H
Imagine a cube of carbon atoms, with a single hydrogen attached at each of the 8 corners. That way we have complete symmetry, since all of the bonds, carbons and hydrogens have the identical environment.