   );
 }
 
+vec2 scene1(vec3 pos) {
+  return bloodVein(pos);
+}
 /*
 vec2 scene1(vec3 pos) {
   // Blood vein thing

  );
}
*/
vec2 scene13(vec3 pos) {
  // Yet another tunnel
  // float plasma1 = calcPlasma(pos.x, pos.y, pos.z, a / 10.0);
  return vec2(
    // tunnel shape
    sdBloodVein2(pos + vec3(3.,-1.,1.)),

    // blobby surface
    // + 0.05 * sin(10.0 * pos.x) * sin(10.0 * pos.y) * sin(10.0 * pos.z),

    // color
    10.0 * a
  );
}

vec2 scene14(vec3 pos) {
  // Blood cell thing v2

  return (1. - c * .25) * (cos(p.x) + sin(p.y) + sin(p.z)) / 20. * (2. * (sin(a / 20.) + 1.15));
}

float sdBloodVein(vec3 p) {
  vec3 c = vec3(2.,3.,5.);
  return -(length(p.xy-c.xz)-c.y);
}

float sdBloodVein2(vec3 p) {
  // the first constant sets size of torus
  // second sets size of middle
  return -(length(vec2(length(p.xz)-4.,p.y)) - 1.5);
}


vec2 heart(vec3 p) {
  float plasma1 = calcPlasma(p.x, p.y, p.z, a / 10.);
  float hue = sin(plasma1) * 100. + a * 10.;
