Stjerneformet polyeder.
Dette ikke-konvekse polyeder er dannet af fem regulære tetraedre indskrevet i et regulært dodekaeder. Det har 60 flader, 150 kanter og 92 hjørner.
Det er i øvrigt brugt af Escher som basis for træskærearbejdet "Polyeder med blomster". (Maurits Cornelis Escher, Veelvlak met bloemen, ahorn, 1958).
Du kan dreje figuren ved at trække med musen. Hvis du holder musen nede, skifter markøren, og du kan trække figuren. Du kan zoome med musehjulet (eller ved at pinche).
Figure3D figure = Position [0,0] Size [x,y] Origin [x/2,y/2] Unit x/5 Angles [30,-30,0] Color "white" Dynamic;
Variable sintop = 2/sqrt(5);
Variable gr36 = pi/5;
Variable r1 = 1;
Variable r2 = r1*(sqrt(5)+1)/2;
Variable edge = r1*2*sin(gr36);
Variable h2 = edge*sin(gr36)/2*sintop;
Variable h1 = h2 + edge*cos(gr36/2)*sintop;
Variable dir0 = [cos(0*gr36),sin(0*gr36),0];
Variable dir1 = [cos(2*gr36),sin(2*gr36),0];
Variable dir2 = [cos(4*gr36),sin(4*gr36),0];
Variable dir3 = [cos(6*gr36),sin(6*gr36),0];
Variable dir4 = [cos(8*gr36),sin(8*gr36),0];
Net test =
Points
r1*dir0+[0,0,h1], r1*dir1+[0,0,h1], r1*dir2+[0,0,h1], r1*dir3+[0,0,h1], r1*dir4+[0,0,h1],
r2*dir0+[0,0,h2], r2*dir1+[0,0,h2], r2*dir2+[0,0,h2], r2*dir3+[0,0,h2], r2*dir4+[0,0,h2],
-r2*dir0+[0,0,-h2], -r2*dir1+[0,0,-h2], -r2*dir2+[0,0,-h2], -r2*dir3+[0,0,-h2], -r2*dir4+[0,0,-h2],
-r1*dir0+[0,0,-h1], -r1*dir1+[0,0,-h1], -r1*dir2+[0,0,-h1], -r1*dir3+[0,0,-h1], -r1*dir4+[0,0,-h1]
Lines
[0,8], [0,14], [0,17], [8,14], [14,17], [17,8],
[1,9], [1,10], [1,18], [9,10], [10,18], [18,9],
[2,5], [2,11], [2,19], [5,11], [11,19], [19,5],
[3,6], [3,12], [3,15], [6,12], [12,15], [15,6],
[4,7], [4,13], [4,16], [7,13], [13,16], [16,7]
Faces
[0,8,14], [17,8,14], [0,17,14], [0,8,17],
[1,9,10], [18,9,10], [1,18,10], [1,9,18],
[2,5,11], [19,5,11], [2,19,11], [2,5,19],
[3,6,12], [15,6,12], [3,15,12], [3,6,15],
[4,7,13], [16,7,13], [4,16,13], [4,7,16];
Net cut = Cut test test Constant;
Scene scene = test Color "black" "rgba(1,1,1,0)", cut Color "black" "rgba(1,1,1,0)";