The LOL isosurfaces of neutral allene are shown in Figure . The total electron density and kinetic energy density are independent of the MO representation and the LOL isosurface is identical whether calculated in the rectilinear or the helical representation of the MOs. In the neutral species these isosurfaces are highly symmetric with no helical features at the bifurcation points of the π-electron basins. When computed from the density arising of a single MO instead, namely the HOMO and HOMO-1, a resemblance to the corresponding MO is observed. This is to be expected because the electron density from a single MO will resemble the shape of the isolated MO. Thus, the LOL isosurfaces based on the degenerate HOMO and HOMO-1 of allene have helical topology if the helical representation is used, but a more localized linear topology if the rectilinear representation is used. The same pattern is seen in spiropentadiene (Figure ) with no helicity in the topology of the total density, while the helicity is revealed in single MO calculations. It is clear that the helical MOs cannot affect the ground-state electron delocalization of allene and spiropentadiene. In the neutral species where π-MOs of both helicities are always doubly occupied, any helical conjuga-tion effect cancels due to the dual-helicity of the MOs.