Hello everyone, i would appreciate any suggestion you could give me to solve this

I'm trying to attach a couple of leads to my structure, I have the code for both, but I want to know how to make that both leads begin with the same atom,

In the code below you can see that the left lead starts in a gray atom, while the lead in the right side starts in the couple of atoms blue and yellow, if I increase the size of the structure it only creates another primitive cell and the case is the same

Is there a way to make that the right lead starts in a gray atom as the left lead, like only creating half primitive cell?

Thanks in advance
Here is the code

import kwant
from matplotlib import pyplot

%matplotlib tk

PrimVec = [(3.176, 0, 0), (1.588, 2.7504, 0), (0, 0, 17.49)]
base =  [(0, 0, 0), (1.588, 0.9168, 0.8745), (0, 0, 1.749)]
lat = kwant.lattice.general(prim_vecs = PrimVec, basis = base)
d, e, f= lat.sublattices


def make_cuboid(t=1.0, a=15, b=10, c=5):
    def cuboid_shape(pos):
        x, y, z = pos
        return 0 <= x < a and 0 <= y < b and 0 <= z < c 
    syst = kwant.Builder()
    syst[lat.shape(cuboid_shape, (0, 0, 0))] = 4 * t
    hoppings = (((1, 0, 0), d, e), ((0, 0, 0), d, e),((0, 1, 0), d, e), ((0, 0, 0), f, e), ((1, 0, 0), f, e), ((0, 1, 0), f, e))
    syst[[kwant.builder.HoppingKind(*hopping) for hopping in hoppings]] = -6
    lead = kwant.Builder(kwant.TranslationalSymmetry((-3.176, 0, 0)))
    def lead_shape(pos):
        return 0 <= pos[1] < b and 0 <= pos[2] < c
    lead[lat.shape(lead_shape, (0, 0, 0))] = 4 * t
    lead[[kwant.builder.HoppingKind(*hopping) for hopping in hoppings]] = -6
    syst.attach_lead(lead)
    syst.attach_lead(lead.reversed())
    return syst

   
def main():   
   
    syst = make_cuboid(a=30, b=14, c=4)   
    def family_colors(site): 
        if site.family == d:
            return 'yellow'
        elif site.family == e:
            return 'gray'
        else:
            return 'blue'
    kwant.plot(syst, site_size=0.25, site_lw=0.025, hop_lw=0.05,
               site_color=family_colors)
    syst = syst.finalized()


if __name__ == '__main__':
    main()