> with(plots):plotsetup(window);
> fieldplot([x,y],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> fieldplot([x,0],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> fieldplot([0,-y],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> fieldplot([y,0],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> fieldplot([0,-x],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> fieldplot([-y,x],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> fieldplot([y,x],x=-3..3,y=-3..3,grid=[6,6],arrows=thick,scaling=constrained);
> plot3d([cos(v),sin(v),u],u=0..2,v=0..4);
> plot3d([(2+u)*cos(2*v),(2+u)*sin(2*v),v],u=0..2,v=0..4);
> plot3d([u*cos(v),u*sin(v),u],u=0..2,v=0..4);
> plot3d([sin(u)*cos(v),sin(u)*sin(v),cos(u)],u=0..2,v=0..4);