diff --git a/app-proto/inversive-display/src/inversive.frag b/app-proto/inversive-display/src/inversive.frag
index c6fed13..2e185a5 100644
--- a/app-proto/inversive-display/src/inversive.frag
+++ b/app-proto/inversive-display/src/inversive.frag
@@ -193,15 +193,13 @@ void main() {
     if (debug_mode) {
         // at the bottom of the screen, show the color scale instead of the
         // layer count
-        if (gl_FragCoord.y < 10.) layer_cnt = 2 * int(8. * gl_FragCoord.x / resolution.x);
+        if (gl_FragCoord.y < 10.) layer_cnt = int(16. * gl_FragCoord.x / resolution.x);
         
         // convert number to color
-        vec3 color;
-        if (layer_cnt % 2 == 0) {
-            ivec3 bits = layer_cnt / ivec3(2, 4, 8);
-            color = mod(vec3(bits), 2.);
-        } else {
-            color = vec3(0.5);
+        ivec3 bits = layer_cnt / ivec3(1, 2, 4);
+        vec3 color = mod(vec3(bits), 2.);
+        if (layer_cnt % 16 >= 8) {
+            color = mix(color, vec3(0.5), 0.5);
         }
         outColor = vec4(color, 1.);
         return;