本图片使用POV-Ray创作.

我，本作品著作权人，释出本作品至公有领域。这适用于全世界。 在一些国家这可能不合法；如果是这样的话，那么： 我无条件地授予任何人以任何目的使用本作品的权利，除非这些条件是法律规定所必需的。

This image was created using POV-Ray for Windows, version 3.6. The image was rendered to an 1800 x 1800 square, using 0.3 anti-aliasing, and then cropped and compressed using pngcrush.

#include "colors.inc"

background { color White }

global_settings { assumed_gamma 1.0}

camera
  {
  location <0, 0, -25>
  right <1,0,0> up <0,1,0>
  look_at  <0, 0, 0>
  angle 5
  }

light_source
  {
  <0, 20, -50>
  color White
  area_light <5, 0, 0>, <0, 5, 0>, 10, 10  /* very slow, decrease 10 to 2 for experiments */
  adaptive 3
  }

#declare r_tube = 0.06;  // thickness (radius) of tube

sphere_sweep
  {
  cubic_spline 99,
  <-0.0723992,-0.451662,0.10003>, r_tube
  <-0.119342,-0.545443,0.0150406>, r_tube
  <-0.111193,-0.633971,-0.0833129>, r_tube
  <-0.0486854,-0.706082,-0.165866>, r_tube
  <0.0548824,-0.749055,-0.216438>, r_tube
  <0.176386,-0.757846,-0.226971>, r_tube
  <0.293134,-0.735233,-0.198633>, r_tube
  <0.389378,-0.687792,-0.139715>, r_tube
  <0.457729,-0.621616,-0.0623503>, r_tube
  <0.497676,-0.539679,0.019862>, r_tube
  <0.51252,-0.442059,0.0925756>, r_tube
  <0.506703,-0.329687,0.140658>, r_tube
  <0.485701,-0.209375,0.150052>, r_tube
  <0.459053,-0.0940421,0.113473>, r_tube
  <0.442833,0.00597527,0.0374574>, r_tube
  <0.453956,0.0932972,-0.055734>, r_tube
  <0.496379,0.181628,-0.135889>, r_tube
  <0.55531,0.282012,-0.178037>, r_tube
  <0.606838,0.392615,-0.171696>, r_tube
  <0.63067,0.50107,-0.121687>, r_tube
  <0.616049,0.592912,-0.0429731>, r_tube
  <0.561376,0.656913,0.0452135>, r_tube
  <0.47222,0.686706,0.122814>, r_tube
  <0.360345,0.681885,0.171002>, r_tube
  <0.242287,0.650074,0.175456>, r_tube
  <0.134108,0.608189,0.13171>, r_tube
  <0.0421477,0.578723,0.0496811>, r_tube
  <-0.0420036,0.578723,-0.0470477>, r_tube
  <-0.133963,0.608202,-0.12909>, r_tube
  <-0.24213,0.650087,-0.172823>, r_tube
  <-0.360201,0.681898,-0.168355>, r_tube
  <-0.472076,0.686732,-0.120154>, r_tube
  <-0.561219,0.656926,-0.0425408>, r_tube
  <-0.615891,0.592912,0.0456327>, r_tube
  <-0.630513,0.50107,0.124334>, r_tube
  <-0.606681,0.392602,0.174356>, r_tube
  <-0.555153,0.281986,0.18071>, r_tube
  <-0.496209,0.181615,0.138562>, r_tube
  <-0.453733,0.0933365,0.0583937>, r_tube
  <-0.442518,0.00614561,-0.0348894>, r_tube
  <-0.458686,-0.0936752,-0.111127>, r_tube
  <-0.4854,-0.208851,-0.1481>, r_tube
  <-0.506611,-0.32915,-0.139243>, r_tube
  <-0.512756,-0.441718,-0.091724>, r_tube
  <-0.498292,-0.539757,-0.0195344>, r_tube
  <-0.458725,-0.622258,0.0622455>, r_tube
  <-0.390702,-0.689036,0.139348>, r_tube
  <-0.294707,-0.737014,0.198214>, r_tube
  <-0.178103,-0.759994,0.226775>, r_tube
  <-0.0565725,-0.751321,0.216778>, r_tube
  <0.0472574,-0.708139,0.167006>, r_tube
  <0.110197,-0.635503,0.0853698>, r_tube
  <0.118818,-0.546256,-0.0121583>, r_tube
  <0.0722944,-0.451833,-0.0966895>, r_tube
  <-0.0120141,-0.357855,-0.13057>, r_tube
  <-0.103961,-0.27749,-0.0966109>, r_tube
  <-0.186121,-0.22832,-0.0123548>, r_tube
  <-0.266499,-0.209821,0.0865751>, r_tube
  <-0.363411,-0.202995,0.166796>, r_tube
  <-0.479386,-0.188858,0.20631>, r_tube
  <-0.597431,-0.157585,0.196681>, r_tube
  <-0.695012,-0.106515,0.143292>, r_tube
  <-0.754689,-0.0379674,0.0611843>, r_tube
  <-0.767201,0.0424631,-0.0303694>, r_tube
  <-0.731355,0.127152,-0.111127>, r_tube
  <-0.654489,0.207504,-0.161935>, r_tube
  <-0.553227,0.276274,-0.168224>, r_tube
  <-0.451034,0.332204,-0.125605>, r_tube
  <-0.369254,0.384676,-0.0443357>, r_tube
  <-0.315459,0.450498,0.0516332>, r_tube
  <-0.279496,0.54103,0.132837>, r_tube
  <-0.24268,0.651515,0.17581>, r_tube
  <-0.191532,0.762669,0.170792>, r_tube
  <-0.123207,0.85134,0.122369>, r_tube
  <-0.0424622,0.9,0.0449908>, r_tube
  <0.0426587,0.899987,-0.0423836>, r_tube
  <0.123391,0.851314,-0.119748>, r_tube
  <0.191715,0.76263,-0.168172>, r_tube
  <0.242864,0.651463,-0.173176>, r_tube
  <0.279666,0.540991,-0.13019>, r_tube
  <0.315617,0.450459,-0.0489736>, r_tube
  <0.369399,0.384624,0.0469953>, r_tube
  <0.451165,0.332126,0.128264>, r_tube
  <0.553358,0.276169,0.170871>, r_tube
  <0.65462,0.207399,0.164529>, r_tube
  <0.731473,0.12706,0.113669>, r_tube
  <0.767254,0.0423976,0.0328456>, r_tube
  <0.754637,-0.0379805,-0.0587736>, r_tube
  <0.694828,-0.106423,-0.140894>, r_tube
  <0.597117,-0.157375,-0.194218>, r_tube
  <0.478993,-0.188583,-0.20369>, r_tube
  <0.363044,-0.202746,-0.163953>, r_tube
  <0.266289,-0.209716,-0.0834963>, r_tube
  <0.186121,-0.228412,0.0156171>, r_tube
  <0.104105,-0.2777,0.099978>, r_tube
  <0.0121452,-0.358012,0.13399>, r_tube
  <-0.0723992,-0.451662,0.10003>, r_tube
  <-0.119342,-0.545443,0.0150406>, r_tube
  <-0.111193,-0.633971,-0.0833129>, r_tube
  pigment { color rgb <0,0.25,1> }
  finish          
    {
    ambient 0.15
    diffuse 0.85
    brilliance 2
    phong 0.25
    phong_size 7.5
    }
  }

plane
  {
  <0,0,-1>, -0.33
  pigment { color White }
  finish
    {
    ambient 0.35
    diffuse 0.65
    }
  }