-- -*- M2-comint -*- {* hash: 2016434943 *}

i1 : normalFan crossPolytope 3

o1 = {ambient dimension => 3         }
      number of generating cones => 6
      number of rays => 8
      top dimension of the cones => 3

o1 : Fan

i2 : C1 = posHull matrix {{2,2},{1,-1}};

i3 : C2 = posHull matrix {{2,-2},{1,1}};

i4 : C3 = posHull matrix {{-2,-2},{1,-1}};

i5 : C4 = posHull matrix {{-2,2},{-1,-1}};

i6 : F = fan {C1,C2,C3,C4}

o6 = {ambient dimension => 2         }
      number of generating cones => 4
      number of rays => 4
      top dimension of the cones => 2

o6 : Fan

i7 :