diff --git a/src/main.ts b/src/main.ts
index ee83786..e4f202c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,8 +1,8 @@
-import { line, group, translate, asSvg, svgDoc, scale } from "@thi.ng/geom";
+import { line, group, translate, asSvg, svgDoc, scale, flip } from "@thi.ng/geom";
 import { $canvas } from "@thi.ng/rdom-canvas";
 import { reactive, sync } from "@thi.ng/rstream";
 import { $compile, $input } from '@thi.ng/rdom'
-import { cycle, takeWhile, comp, mapIndexed, range, iterator, map, mapcat } from "@thi.ng/transducers"
+import { cycle, takeWhile, comp, mapIndexed, range, iterator, map, mapcat, reverse } from "@thi.ng/transducers"
 import { vec2 } from "@thi.ng/vectors"
 
 const cellSize_ = "12"
@@ -71,8 +71,19 @@ const scene = sync({
   const ySeeds = seededGrid(ys, yCells)
 
   const yLines = iterator(
-    mapcat(([x, seed]) =>
-      map(([y1, y2]) => scale(line([x, y1], [x, y2]), cellSize), stitches(seed, yCells))),
+    mapcat(([x, seed]) => {
+      // optimization for quicker drawing: when we're in an odd row,
+      // reverse drawing direction
+      const inEvenRow = x % 2 === 0
+      return iterator(
+        comp(
+          map(([y1, y2]) => line([x, y1], [x, y2])),
+          map(l => inEvenRow ? l : flip(l)),
+          map(l => scale(l, cellSize))
+        ),
+        inEvenRow ? stitches(seed, yCells) : reverse(stitches(seed, yCells))
+      )
+    }),
     xSeeds
   )