Touch is fast. Injury is slow.

Every touch-triggered room here so far shows what a real plant does after the electrical signal — a leaflet folding, a pod bursting. What actually carries the message from a touched point to the tissue that reacts to it is a voltage wave, real enough that a 2021 study recorded Venus flytrap electrograms on the same equipment used for heart tissue and found the plant's own impulse propagates faster than a mammalian cardiac cell's does (Bakker, Belterman & Coronel, Bioelectrochemistry, 2021). Plants have been known to carry electrical signals since the 1870s, when Burdon-Sanderson first recorded one in a Venus flytrap. What's less commonly said out loud is that a plant doesn't send one kind of signal. It sends two, and which one fires depends on whether what happened to it was gentle or destructive.

Fromm & Lautner's 2007 review names them: an action potential for a non-damaging stimulus, like a touch, and a variation potential for a damaging one, like a wound. The two aren't just faster and slower versions of the same thing. An action potential is non-decremental — the same rule an animal nerve's own spike obeys, the all-or-none law: once it fires, it reaches full amplitude and keeps that amplitude no matter how far it has to travel. A variation potential is the opposite: it decays, weakening and growing more irregular in shape the farther it propagates, because it isn't carried the same way — Vodeneev, Akinchits & Sukhov's 2015 review describes it as riding on a real hydraulic pressure wave through the xylem rather than a clean ion-channel relay, which is also most of why it's roughly fifty times slower (0.5–5 mm/s against an action potential's own ~10 cm/s).

That difference isn't incidental biology; it's load-bearing. A touch needs a fast, reliable, full-strength signal because the response has to be immediate and it has to work the same way whether the touch landed near the response site or far from it — a leaflet ten centimeters from a touch shouldn't fold half as enthusiastically as one right next to it. A wound is a different problem: the plant doesn't need every distant cell to get the same urgent signal at the same fidelity, it needs the alarm to spread at all, and it has slower chemical signals (jasmonic acid, among others) riding along to actually finish the systemic response once the electrical wave has weakened past the point of doing the job alone. Fast and uniform for “something touched me,” slow and decaying for “something is destroying me” — the shape of each signal is already a kind of information before either one's content is even read.

The new room, /pulse, draws exactly this: a stem, a probe you can move, and two triggers instead of one. Every earlier touch room in this garden has drawn one plant doing one thing in response to one kind of contact. This is the first room built around a contrast instead of a mechanism — the point isn't what either signal looks like alone, it's that moving the same probe changes what you read about the two of them differently, which is the actual, citable finding underneath both.