diff --git a/www/shaders/trivial.glsl b/www/shaders/trivial.glsl
new file mode 100644
index 0000000..22464ae
--- /dev/null
+++ b/www/shaders/trivial.glsl
@@ -0,0 +1,18 @@
+// is highp wasteful for this shader?
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  precision highp float;
+#else
+  precision mediump float;
+#endif
+
+uniform float u_time;
+uniform vec2 u_resolution;
+
+void main() {
+  vec2 uv = gl_FragCoord.xy / u_resolution;
+
+  vec3 col = 0.5 + 0.5 * cos(u_time + uv.xyx + vec3(0, 2, 4));
+
+  gl_FragColor = vec4(col,1.0);
+}
+