Rung

He taught the two constraints that made the ladder work.

"Two rules, and they're both strict," Rung said. "First: exactly one letter changes per step — not two, not zero. Second: every step must land on a real word. You can't hop through gibberish to get where you're going; CO L D to C X L D is illegal, even if it'd be convenient. Those two rules are what make it a puzzle instead of a mess. The tight constraint is the whole game."

The subtext the older solvers heard was about change itself — that even a total transformation is reachable through a chain of small, legitimate steps, and that the discipline of every step being real is exactly what makes the journey trustworthy.

Rung shared the strategy that turned guessing into solving.

"Beginners change letters at random and wander forever," he said. "The trick is to look at your start and your target and ask: which letters already match? COLD to WARM — no letters match yet, so I need to migrate all four, one at a time, keeping a real word each step. So I fix the letters I can while the others give me valid words to stand on. I don't wander. I steer — every step both a legal rung AND a step toward the target."

The Host challenged him: turn HEAD into TAIL.

"Four letters, none shared — the hardest kind," Rung said, unbothered. "HEAD. I need a T at the front and an L at the end eventually, but I have to keep landing on real words. HEAD to HEAL — swap D for L, real word, and I've placed my final letter early. HEAL to TEAL — swap H for T, real word, front letter placed. TEAL to TALL — swap E for A? TALL, real. TALL to TAIL — swap the second L for I. TAIL." He climbed it in the air, rung by rung. "Head to tail. Every step legal. I placed the hard letters when a real word let me, and let the middle sort itself."

The solver counted the rungs. "Four small steps, and you crossed the whole word."