Nothing reaches the summitunexamined.
Tirith stands between a plan and the change it would make, so a plan that breaks a rule you have written does not reach apply. The mark says that before a word does. It is not a castle and not a tower — it is a city seen from above, reduced until only the rule is left.
The city the name comes from
Minas Tirith held because of how it was laid out. Seven walls, a single gate in each, and every gate set on the far side of the one below it, so anyone who broke the first was walking sideways by the time he met the second.
None of which is a wall being strong. A single wall, however thick, is one problem and it is solved once. Seven walls with their gates deliberately out of line is a different problem: it cannot be solved once and it cannot be solved quickly, because the work of getting through one is spent again at the next, and again after that.
The defence was never the stone. It was the order the gates were in.
A city in plan, opened up
The city is the argument, not the decoration. No castle and no tower appear in the mark. What carries over is the plan, in four moves.
- 01
Seven walls
Seven walls climbing a spur of rock, one gate in each, and no gate on the same side as the one below it. Anyone climbing spent the whole ascent turning. Seen from above, that is a set of broken rings.
- 02
Down to two
Seven walls is a drawing. Two is a mark. One band, broken twice, gates set opposite, which is the fewest breaks that still make a sequence rather than a hole.
- 03
The climb
The inner edge steps in behind each gate, so the band is never a constant ring. That is the climb in plan, and it is also what keeps the shape from settling into a target.
- 04
Close the ring
The wall comes back to full thickness and the ring closes, cut through on both diagonals. What survives of the corridor is the step on the inner edge — the climb, still legible in a shape that no longer has a way in.
Opposed gates are the product
A change arrives at the first wall, gets checked, and comes out facing the wrong way for the second. It cannot run the walls in a straight line and it cannot skip one.
That is Tirith, drawn as a floor plan. A plan arrives at the gate before anything is applied, every rule you have written gets its say on it in turn, and the change either comes out the far side or it does not move at all. A rule that passes does not excuse the one behind it, and where the rules are joined by and, one refusal is the whole verdict.
Which is the refusal the city was built on. No single move gets you to the top, and nothing reaches production without walking the whole route.
- Why it is not the parent mark
- StackGuardian watches what reaches production. Tirith is the part that decides whether it should, so the mark inherits the family’s geometry and none of the parent’s shapes.
- Why it has no up
- Rotational rather than mirror symmetry, which is why it holds at any angle and reads the same in an avatar as in a favicon.