The bodygraph has two pressure centres, one at each end, and they are structurally unlike the rest.
At the top is the Head, holding Gates 61, 63 and 64. It is not a motor and it produces no energy for action. What it produces is pressure to think: inspiration in Gate 61, doubt in Gate 63, confusion in Gate 64. That pressure passes down into the Ajna, which turns it into concept, and from the Ajna into the Throat, which turns concept into speech.
At the bottom is the Root, an adrenal pressure centre driving activity, stress and the urge to be done with things.
The system's claim about the top of the graph is worth stating clearly, because it is counter-intuitive and it is consistent. Human Design holds that mental pressure is not for the person experiencing it. The Head and Ajna exist, in this account, to produce thought that is useful to others; they are not designed to run one's own life, and the attempt to decide personal matters with the mind is treated as the primary source of difficulty the system claims to address. Hence the repeated instruction that the mind is a passenger and not the driver.
Gate 64 carries confusion specifically, and the system treats confusion as a pressure that resolves on its own schedule rather than a problem to be solved by more thinking. Paired with Gate 47 in the Ajna, it forms the channel of Abstraction, in which impressions are worked over until a realisation arrives.
That the sixty-fourth hexagram of the I Ching is called Before Completion, and depicts a young fox getting its tail wet just short of the far bank, makes the correspondence here a genuinely apt one. It is also, like all of them, a correspondence assigned in 1987.