 vec2 scene0(vec3 pos) {
   return opU(
     heart(pos),
-    bloodCellField(pos)
-  );
+    bloodCellField(pos));
+  //);
 }
 
 /*

    // ta = camera direction (where the camera is looking)
    // cr = camera rotation
    //vec3 ro = vec3( -.5+3.5*cos(.1*a), 1.0, .5 + 4.0*sin(.1*a) );
    vec3 ro = vec3( -.5+.2*cos(.1*a), 1., .0 + 2.*sin(.1*a) );
    vec3 ta = vec3( .0 );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, .0 );

  // float plasma1 = calcPlasma(pos.x, pos.y, pos.z, a / 10.0);
  return vec2(
    // tunnel shape
    sdBloodVein(pos + vec3(3.,-1.,1.)),

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