Greg C's Ribbed Trench:

This space curve was produced using the following Maple commands:

> x:=t;
> y:=sin(t);
> z:=-cos(t)^2;

                                x := t


                             y := sin(t)


                                        2
                            z := -cos(t)

> with(plots):
> spacecurve([x,y,z],t=0..8*Pi,numpoints=1000,
>   axes='NORMAL');