diff --git a/static/script.js b/static/script.js
index b52ba07f..e5c595e4 100644
--- a/static/script.js
+++ b/static/script.js
@@ -1777,25 +1777,24 @@ function render(players) {
 
 /* ---------- rendering trails ------------------------------- */
 function renderTrails(trailData) {
-  trailsContainer.innerHTML = '';
-  const byChar = trailData.reduce((acc, pt) => {
-    (acc[pt.character_name] = acc[pt.character_name] || []).push(pt);
-    return acc;
-  }, {});
-  for (const [name, pts] of Object.entries(byChar)) {
-    if (pts.length < 2) continue;
-    const points = pts.map(pt => {
-      const { x, y } = worldToPx(pt.ew, pt.ns);
-      return `${x},${y}`;
-    }).join(' ');
-    const poly = document.createElementNS('http://www.w3.org/2000/svg', 'polyline');
-    poly.setAttribute('points', points);
-    // Use the same color as the player dot for consistency
-    poly.setAttribute('stroke', getColorFor(name));
-    poly.setAttribute('fill', 'none');
-    poly.setAttribute('class', 'trail-path');
-    trailsContainer.appendChild(poly);
-  }
+    trailsContainer.innerHTML = '';
+    // Build point strings directly - avoid intermediate arrays
+    const byChar = {};
+    for (const pt of trailData) {
+        const { x, y } = worldToPx(pt.ew, pt.ns);
+        const key = pt.character_name;
+        if (!byChar[key]) byChar[key] = { points: `${x},${y}`, count: 1 };
+        else { byChar[key].points += ` ${x},${y}`; byChar[key].count++; }
+    }
+    for (const name in byChar) {
+        if (byChar[name].count < 2) continue;
+        const poly = document.createElementNS('http://www.w3.org/2000/svg', 'polyline');
+        poly.setAttribute('points', byChar[name].points);
+        poly.setAttribute('stroke', getColorFor(name));
+        poly.setAttribute('fill', 'none');
+        poly.setAttribute('class', 'trail-path');
+        trailsContainer.appendChild(poly);
+    }
 }
 /* ---------- selection centering, focus zoom & blink ------------ */
 function selectPlayer(p, x, y) {