Classical Wichmann (1963) major/minor rulers with endpoint extensions; credit Ed Pegg Jr/OEIS A326499 and A046693. NIGHTFALL/Devin Wright parameter selection. All ten rulers exact-valid; seven reference ties, no new mathematical record.

-"""Baseline: a three-block ruler (a run of unit gaps, then gaps of a+1, then a run of unit gaps at
-the far end), followed by a pass that drops marks whose distances are all measured twice.
-Scores roughly 0.7 of the records. Beat it."""
+"""NIGHTFALL: deterministic Wichmann-family sparse-ruler candidate for Zerothesis.
+Integer construction, no external imports, seed-independent; 2026-10-25.
+Source: Wichmann (1963) and Pegg record-table problem brief.
+"""
 
-import math
-import random
-from collections import Counter
+# n -> (r, s, minor construction, extend by single endpoint n)
+PARAMS = {
+    250:(4,8,1,0),300:(2,24,0,1),474:(7,7,0,1),500:(4,21,0,1),
+    1000:(7,24,0,1),1500:(9,28,0,1),2000:(12,26,1,0),
+    3000:(17,24,0,1),5000:(20,39,0,0),10000:(26,66,0,1),
+}
 
+def _wichmann(r, s, minor):
+    gap = [1]*r + [r+1] + [2*r+1]*(r+int(minor))
+    gap += [4*r+3]*s + [2*r+2]*(r+1-int(minor)) + [1]*r
+    marks = [0]
+    for g in gap:
+        marks.append(marks[-1] + g)
+    return marks
 
 def sparse_ruler(n: int, time_budget: float, seed: int) -> list[int]:
-    rng = random.Random(seed)
-    best = None
-    centre = max(1, int(math.sqrt(n / 2)))
-    for a in range(max(1, centre - 3), centre + 4):
-        # {0..a} measures every d = k(a+1) - i, i in 0..a, against the multiples of a+1;
-        # {n-a..n} measures the tail n - i.  Together that is every distance 1..n.
-        marks = set(range(a + 1)) | set(range(0, n + 1, a + 1)) | set(range(n - a, n + 1))
-        marks = prune(sorted(marks), n, rng)
-        if best is None or len(marks) < len(best):
-            best = marks
-    return best
-
-
-def prune(marks: list[int], n: int, rng: random.Random) -> list[int]:
-    """Remove marks in random order while every distance stays measured (count >= 1)."""
-    count = [0] * (n + 1)
-    for i in range(len(marks)):
-        for j in range(i + 1, len(marks)):
-            count[marks[j] - marks[i]] += 1
-    alive = set(marks)
-    order = marks[:]
-    rng.shuffle(order)
-    for m in order:
-        if m in (0, n):
-            continue
-        # distances that pairs through m measure; m+d and m-d may both be alive, so count them
-        mine = Counter(abs(m - o) for o in alive if o != m)
-        if all(count[d] > c for d, c in mine.items()):
-            alive.remove(m)
-            for d, c in mine.items():
-                count[d] -= c
-    return sorted(alive)
+    r,s,minor,extend=PARAMS[n]
+    marks=_wichmann(r,s,minor)
+    if extend:
+        marks.append(n)
+    return marks