| make dodecaedre
dir <obey$dir>
|dcadre  10 faces:
|https://fr.wikipedia.org/wiki/D%C3%A9ca%C3%A8dre
|Usage: dodec angleX angleY angleZ
dodec 45 45 45 >Decod.decahedron
|Icosadre  20 faces
|"Usage: icos angleX angleY angleZ
icos  45 45 45 >decod.Icosahedron
| icosahedron dual dodecahedron :  12 faces
| https://fr.wikipedia.org/wiki/Dod%C3%A9ca%C3%A8dre
|
|icosi 45 45 45 >decod.Icosahedroni

|compute intersection of two lines
| Usage:  x00 y00 x01 y01 x10 y10 x11 y11
intersect 100 100 1000 1000 120 150 900 320 >decod.intersect
