diff --git a/src/lib/client/color.js b/src/lib/client/color.js
index 8e538da..7813352 100644
--- a/src/lib/client/color.js
+++ b/src/lib/client/color.js
@@ -4,6 +4,9 @@ import seedrandom from "seedrandom";
  * @typedef {{r: number, g: number, b: number}} rgb
  */
 
+/** @type {rgb} */
+export const black = {r: 0, g: 0, b: 0};
+
 /**
  * @param {seedrandom.PRNG} random 
  * @returns {rgb}
@@ -55,14 +58,16 @@ export function generateQuadColors(seed) {
   const c3 = createColor(r);
   const c4 = createColor(r);
 
+  const blackCorner = Math.floor(r.quick() * 4);
+
   return {
     c1: c1,
     c2: c2,
     c3: c3,
     c4: c4,
-    c13: mixColors(c1, c3),
-    c14: mixColors(c1, c4),
-    c23: mixColors(c2, c3),
-    c24: mixColors(c2, c4),
+    c13: blackCorner == 0 ? black : mixColors(c1, c3),
+    c14: blackCorner == 1 ? black : mixColors(c1, c4),
+    c23: blackCorner == 2 ? black : mixColors(c2, c3),
+    c24: blackCorner == 3 ? black : mixColors(c2, c4),
   };
 }