diff --git a/src/shadertoy.c b/src/shadertoy.c
index 2324372..5aff99c 100644
--- a/src/shadertoy.c
+++ b/src/shadertoy.c
@@ -130,6 +130,9 @@ struct location {
   struct {
     unsigned int position;
   } attrib;
+  struct {
+    unsigned int time;
+  } uniform;
 };
 
 int main()
@@ -140,7 +143,7 @@ int main()
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
   //glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GLFW_TRUE);
 
-  GLFWwindow* window = glfwCreateWindow(1200, 1200, "LearnOpenGL", NULL, NULL);
+  GLFWwindow* window = glfwCreateWindow(1600, 1200, "LearnOpenGL", NULL, NULL);
   if (window == NULL) {
     const char* description;
     glfwGetError(&description);
@@ -150,7 +153,7 @@ int main()
   }
   glfwMakeContextCurrent(window);
 
-  glViewport(0, 0, 1200, 1200);
+  glViewport(0, 0, 1600, 1200);
   //glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
   unsigned int vertex_buffer = make_buffer(GL_ARRAY_BUFFER,
@@ -167,6 +170,11 @@ int main()
   printf("attributes:\n  position %u\n",
          location.attrib.position);
 
+  location.uniform.time = glGetUniformLocation(shaderProgram, "time");
+  printf("uniforms:\n  time %u\n",
+         location.uniform.time);
+
+  float time = 0;
   while(!glfwWindowShouldClose(window)) {
     if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
       glfwSetWindowShouldClose(window, true);
@@ -188,6 +196,8 @@ int main()
                           (void*)0
                           );
     glEnableVertexAttribArray(location.attrib.position);
+    glUniform1f(location.uniform.time, time);
+    time += 0.01;
 
     glDrawArrays(GL_TRIANGLES, 0, 6);
 
diff --git a/src/shadertoy.fp.glsl b/src/shadertoy.fp.glsl
index 5b68c64..921762e 100644
--- a/src/shadertoy.fp.glsl
+++ b/src/shadertoy.fp.glsl
@@ -2,7 +2,53 @@
 
 varying vec2 pos_out;
 
+uniform float time;
+
+/*
+vec3 palette(float t) {
+  vec3 a = vec3(0.5, 0.5, 0.5);
+  vec3 b = vec3(0.5, 0.5, 0.5);
+  vec3 c = vec3(1.0, 1.0, 1.0);
+  vec3 d = vec3(0.263, 0.416, 0.557);
+
+  return a + b * cos(6.28318548202514648438 * (c * t + d));
+}
+*/
+
 void main()
 {
-  gl_FragColor = vec4(pos_out, 0, 1);
+  vec2 uv = pos_out;
+  //gl_FragColor = vec4(uv, 0, 1);
+  //gl_FragColor = gl_Color;
+  float d = length(uv);
+
+  //d -= 0.5;
+  //d = abs(d);
+  //d = step(0.1, d);
+  //d = smoothstep(0.0, 0.1, d);
+
+  gl_FragColor = vec4(d, 0, 0, 1);
+
+  /*
+  vec3 col = vec3(1.0, 2.0, 3.0);
+
+  d = sin(d * 8.0 + time)/8.0;
+  d = abs(d);
+  d = 0.02 / d;
+
+  col *= d;
+
+  gl_FragColor = vec4(col, 1);
+  */
+  /*
+  vec3 col = palette(d + time);
+
+  d = sin(d * 8.0 + time)/8.0;
+  d = abs(d);
+  d = 0.02 / d;
+
+  col *= d;
+
+  gl_FragColor = vec4(col, 1);
+  */
 }
diff --git a/src/shadertoy.vp.glsl b/src/shadertoy.vp.glsl
index 32b0712..e5811ca 100644
--- a/src/shadertoy.vp.glsl
+++ b/src/shadertoy.vp.glsl
@@ -7,5 +7,6 @@ varying vec2 pos_out;
 void main()
 {
   gl_Position = vec4(position, 1);
-  pos_out = vec2(position);
+  pos_out = vec2(position.x * 4.0 / 3.0, pos_out.y);
+  //gl_FrontColor = vec4(position.xy, 0, 1);
 }