The line_segments command takes as argument a polyhedron.
line_segments returns and draws the list of the edges of a polyhedron. For example:
| line_segments(polyhedron([0,0,0],[-2,0,0],[2,0,0],[0,2,0],[0,0,2])) |
Individual line segments can be obtained by using the [] operator. For example, the command line
| line_segments(polyhedron([0,0,0],[-2,0,0],[2,0,0],[0,2,0],[0,0,2]))[1] |
returns the second segment.