Hi, I'm experiencing an issue on my cubic construction. It doesn't matter what I try it persists. I think it is a bug, but I'm not sure. I have the following code, and I'm getting that the top site of z at a "x,y" corner is always a different lattice, the botton lattice. If I eliminate "lat_ti" which is green, then this site becomes blue, "lat_tu", but never becomes "lat_sc" as stated. Even if I put this site above the sample, that is, unnconected, this issue mantains. This also was happening before stating colors for the lattices. Link for the plot: https://drive.google.com/file/d/13Z5XnGa-eyJGYJgyM_NGm0onp5MoQs_O/view?usp=s... def make_system(a=1, W=21, L=15, H=4, Hs=6, barrier=1.5, mu=0.4, Delta=0.1, t=1.0): lat_sc = kwant.lattice.cubic(a,name='Supercondutor', norbs=2) lat_tu = kwant.lattice.cubic(a,name='Tunelamento', norbs=2) lat_ti = kwant.lattice.cubic(a,name='TopIns') syst = kwant.Builder() #### Scattering region. #### syst[(lat_ti(x, y, z) for x in range(W) for y in range(L) for z in range(H-1))] = 0 syst[(lat_ti(x, y, z) for x in range(int(W/3),int(2*W/3)) for y in range(L) for z in range(H-1,H))] = 0 syst[(lat_sc(x, y, z) for x in range(int(W/3)) for y in range(L) for z in range(H+1,H+Hs))] = onsite_sc syst[(lat_sc(x, y, z) for x in range(int(2*W/3),W) for y in range(L) for z in range(H+1,H+Hs))] = onsite_sc syst[(lat_sc(W-1, 0, H+Hs+2))] = 0 #bug ? # The tunnel barrier syst[(lat_tu(x, y, z) for x in range(int(W/3)) for y in range(L) for z in range(H-1, H+1))] = onsite_tu syst[(lat_tu(x, y, z) for x in range(int(2*W/3),W) for y in range(L) for z in range(H-1,H+1))] = onsite_tu def family_color(site): if site.family == lat_sc: return 'red' if site.family == lat_ti: return 'green' if site.family == lat_tu: return 'blue' return syst, family_color