Using Maple to display a stella octangula

> with(plots): with(plottools):

```Warning, the name arrow has been redefined
```

```Warning, the name arrow has been redefined
```

Define the eight vertices (corners). Ending each statement with a semicolon causes the computer to show the results.

> p1:=[-1,-1,-1]; p2:=[-1,-1,1]; p3:=[-1,1,-1]; p4:=[-1,1,1]; p5:=[1,-1,-1]; p6:=[1,-1,1]; p7:=[1,1,-1]; p8:=[1,1,1];

Define the two tetrahedra in terms of their polygons. For each polygon list the vertices in the proper order around its perimeter. It helps if you first make a sketch on a piece of paper. Ending the statement with a colon prevents the computer from showing the results.

> tetra1:=polygonplot3d([ [p1,p4,p6], [p1,p4,p7], [p1,p6,p7], [p4,p6,p7] ]):

Give the tetrahedron a color.

> yellowtetra:=display(tetra1,color=yellow):

Display it. You can twirl it around by clicking and dragging. Here we want a semicolon so that we can see it!

> display(yellowtetra,scaling=constrained,orientation=[10,75]);

Make the second tetrahedron.

> tetra2:=polygonplot3d([ [p2,p3,p5], [p2,p3,p8], [p2,p5,p8], [p3,p5,p8] ]):

> orangetetra:=display(tetra2,color=orange):

> display(orangetetra,scaling=constrained,orientation=[10,75]);

Display both tetrahedra.

> display({yellowtetra,orangetetra},scaling=constrained,orientation=[10,75]);

>