I encountered an error when trying to run the demo at the end of the drawCylinder script:
>> pkg install -forge geometry
For information about changes from previous versions of the geometry package, run 'news geometry'.
>> pkg load geometry
>> which drawCylinder
'drawCylinder' is a function from the file /home/abr_ca/octave/geometry-2.1.1/geom3d/drawCylinder.m
>> h = drawCylinder([0 0 0 10 20 30 5],'FaceColor', 'r');
error: __go_draw_axes__: gnuplot (as of v4.2) only supports 3-D filled triangular patches
error: called from
__go_draw_axes__ at line 671 column 18
__go_draw_figure__ at line 172 column 17
__gnuplot_drawnow__ at line 86 column 5
>> quit
......................................................................................................
The line
h = drawCylinder([0 0 0 10 20 30 5],'FaceColor', 'r');