 
   return vec2(
     // tunnel shape
-    sdTunnelThing(p)
+    (1. - c * .25) * (cos(p.x) + sin(p.y) + sin(p.z)) / 20. * (2. * (sin(a / 20.) + 1.15))
 
     // blobby surface
     + (1. - c) * .05 * sin(10. * p.x) * sin(10. * p.y) * sin(10. * p.z) * sin(plasma1),

  // last scene
  if (a >= end3) {
    res = opMorph(res,
      scene1(pos),

      // Timing
      end3,

  pR(p.yz, 1.);
  p += vec3(.0, .0, a * .1);
  res = opU(res, vec2(sdBloodCell(opRep(p, vec3(3.))), 54.));

  return res;
}

vec2 bloodVein(vec3 pos) {
  return vec2(
