Components of a Great Rhombic Triacontahedron​
​By Sándor Kabai
The great rhombic triacontahedron (GRT) can be considered to be a composition of 30 golden rhombuses (a stellation of the rhombic triacontahedron). This Demonstration shows how the protruding parts (stars) can also be interpreted as parts of a concave rhombic hexecontahedron.
The internal parts are revealed as the shells are removed:
1. the concave rhombic hexecontahedron (CRH)
2. the relationship to the median rhombic triacontahedron (MRT)
3. the rhombic triacontahedron (RT)
The building can be started with the stellation diagram.
In[]:=
fi=GoldenRatio;​​alf=ArcTan[fi];​​bet=ArcTan[1/fi];​​vA={fi,0,fi^2};​​vB={0,1,fi^2};​​vC={-fi,0,fi^2};​​vD={0,-1,fi^2};​​vE={fi+fi^2,-fi,fi^2};​​vF={fi+2fi^2,0,fi^2};​​vG={fi+fi^2,fi,fi^2};​​vH={fi+1,1/fi,fi^2};​​vI={fi+2,0,fi^2};​​vJ={fi+1,-1/fi,fi^2};​​vK={0,-1-2fi,fi^2};​​vL={fi,(-1-2fi)+1,fi^2};​​vM={1/fi,(-1-2fi)+fi,fi^2};​​vO={-1,-fi,fi^2};​​vP={1,-fi,fi^2};​​vR={fi^2,-(1+fi),fi^2};​​vQ={-fi-2fi^2,0,fi^2};​​w={Yellow,Polygon[{vA,vB,vC,vD}]};​​z1={RGBColor[0.8,1,0.6],Polygon[{vK,vP,vD,vO}]};​​z2=Rotate[z1,Pi,{0,0,1}];​​u1={RGBColor[1,0.4,0.7],Polygon[{vK,vL,vM}]};​​u2=Rotate[u1,Pi,{0,0,1}];​​u3=Rotate[{u1,u2},Pi,{1,0,0},{0,0,fi^2}];​​r1={RGBColor[0,1,1],Polygon[{vL,vR,vP,vM}]};​​r2=Rotate[r1,Pi,{0,0,1}];​​r3=Rotate[{r1,r2},Pi,{1,0,0},{0,0,fi^2}];​​v1=Polygon[{vJ,vE,vF,vG,vH,vI}];​​v2=Rotate[v1,Pi,{0,0,1}];​​​​Manipulate[Module[{p0,p1,p2,p3,p4,p5,mrt},​​p0=Rotate[{w,z1,z2,u1,u2,u3,r1,r2,r3,v1,v2},-bet,{0,1,0}];​​p1={If[sw,w,{}],If[z,{z1,z2},{}],If[u,{u1,u2,u3},{}],If[r,{r1,r2,r3},{}],If[v,{v1,v2},{}]};​​p2=Rotate[p1,Pi,{0,1,0}];​​p3=Rotate[{p1,p2},Pi,{0,1,0}];​​p4=Rotate[Rotate[{p1,p2,p3},Pi/2+0.001,{0,1,0}],Pi/2+0.001,{0,0,1}];​​p5=Rotate[Rotate[{p1,p2,p3},Pi/2+0.001,{1,0,0}],Pi/2+0.001,{0,0,1}];​​​​mrt=Table[Rotate[Rotate[{p1,p2,p3,p4,p5},-bet,{0,1,0}],i2Pi/5,{0,0,1}],{i,5}];​​Graphics3D[{p0,mrt},BoxedFalse,SphericalRegionTrue,ImageSize350,ViewAngle0.1,ViewPoint{2,2,10},PlotRange7.2]],​​​​{{sw,False,"rhombic triacontahedron"},{True,False},ControlPlacementLeft,ImageSizeTiny},​​{{z,False,"median rhombic triacontahedron"},{True,False},ControlPlacementLeft,ImageSizeTiny},​​{{r,False,"concave rhombic hexecontahedron"},{True,False},ControlPlacementLeft,ImageSizeTiny},​​{{u,False,"star"},{True,False},ControlPlacementLeft,ImageSizeTiny},​​{{v,False,"great rhombic triacontahedron"},{True,False},ControlPlacementLeft,ImageSizeTiny},​​Delimiter,​​TrackedSymbols{v,r,u,z,sw},SaveDefinitions->True]
Out[]=
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rhombic triacontahedron
median rhombic triacontahedron
concave rhombic hexecontahedron
star
great rhombic triacontahedron