See Section 24.6.5 for parallel lines in the plane.
The parallel command can take its arguments in different ways. It returns and draws a line or plane depending on the arguments.
parallel(point(1,1,1),line(point(0,0,0),point(0,0,1))) |
parallel(line(point(1,0,0),point(0,1,0)),line(point(0,0,0),point(0,0,1))) |
parallel(point(0,0,0),plane(point(1,0,0),point(0,1,0),point(0,0,1))) |
parallel(point(1,1,1),line(point(0,0,0),point(0,0,1)), line(point(1,0,0),point(0,1,0))) |