The marker stops lying, and the rule announces itself

"the marker flips all the time even during a ball being midair.. i am not
sure that a player would get the mechanic intuitively let alone without the
marker".

The flip had a specific cause and it was a design bug, not jitter. With lanes
held and speeds constant, arrival differences never change while bodies walk
— the queue only reorders on a kill or an arrival. The marker flipped because
it showed only q[0] while the rule accepts any near-tie within the slack:
every kill made it jump between tied bodies, so the marker was stricter than
the rule it was explaining. drillLegal() marks the whole slack set now,
bright head and dim ties, which is stable by construction. Measured: zero
head-changes across 12s of walking with no kills.

Learnability, two answers. The rule gets one modal, once per run, on the
mode's own calm court — CLEARANCE DRILL / DROP WHOEVER WOULD REACH YOU FIRST
/ FAST BEATS CLOSE / STREAKS PAY — because "most urgent first" is not
guessable from a chevron alone. And the markers are training wheels that take
themselves off: hidden at streak >= 8 (the streak is the evidence you can
read the court), back on any fault. The teacher steps in exactly when you
demonstrably need it.

31 tests, 15 seeds clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/config.js

@@ -369,9 +369,12 @@ export const TUNE = {
   drillSlack: 0.9,
   drillMultEvery: 4, // correct kills per multiplier step...
   drillMultCap: 5,   // ...capped: a deep streak should feel valuable, not become the whole score
-  drillMark: 1,      // >= 0.5 draws a chevron over the queue head — the CALIBRATION AID, so a
-                     // playtest can check the game's read against the player's. Off for the real
-                     // thing: the marker answers the exact question the mode exists to ask
+  drillMark: 1,      // >= 0.5 draws chevrons over every LEGAL kill (the slack set, bright head,
+                     // dim ties). Training wheels, not a cheat: see drillMarkOff
+  drillMarkOff: 8,   // streak at which the markers hide — you have shown you can read the court, so
+                     // the teacher steps back. Any fault (streak to 0) brings them back. This is the
+                     // learnability answer: the marker teaches, the streak decides when you have
+                     // learned, unlearning re-teaches
   drillOneShot: 0,  // >= 0.5: every drill body drops to 1 hp. OFF after one playtest: "way too easy"
                     // AND a 1 hp body skips every ZWOUND stage, so the gore art never renders.
                     // Also flattens triage — pre-softening a heavy IS the planning layer