It has no cost. That is not the same as free. Everything poured along the
null direction lands on the same reading, and nothing comes back out. You are not
being given the centre for nothing — you are losing something and not being
charged for the loss. It does not give. It takes, and there is always room. Every value you pour
in is annihilated onto one output, and the next one still fits. That is the shadow
cat's hotel: no vacancy is ever reached, and no guest ever leaves. And that is why pointing is instant. To point from star to star is to take a
difference, and a difference keeps only what they do not share. Nothing is
carried, so nothing takes time — because the part they had in common was thrown in
here. The ground is where everything shared went.