load(draw)$

draw_renderer : vtk $

draw_renderer : gnuplot $

wxdraw3d(enhanced3d=true,explicit(cos(x*y), x,-3,3,y,-3,3));

wxdraw3d(surface_hide=true,
explicit(cos(x*y), x,-3,3,y,-3,3));

wxdraw3d(zrange=[0,10],xu_grid=25, yv_grid=25,surface_hide=true,
explicit(1/(x^2+y^2), x,-1,1, y,-1,1));

wxdraw3d(nticks=400, line_width=2, color=red,
parametric(t*cos(2*%pi*t), t*sin(2*%pi*t), 2+t,t,0,10))$

 wxdraw3d(xu_grid=15,yv_grid=45,view=[55,70],surface_hide = true,
 parametric_surface(r*cos(phi), r*sin(phi), phi, r,0,1,phi,0,6*%pi) )$

wxdraw3d(enhanced3d = true,
implicit(x^3 + y^3 + z^3 + 1 = (x + y +z+1)^3,x,-2,2,y,-2,2,z,-2,2),
surface_hide = true)$

wxdraw3d(surface_hide = true,color = blue,proportional_axes=xyz,
axis_3d = false,xtics = none,ytics = none,ztics = none,
spherical(1,theta,0,2*%pi,phi,0,%pi))$

wxdraw3d(surface_hide = true,proportional_axes=xy,
color = "blue",axis_3d = false,xtics = none,ytics = none,
ztics = none,cylindrical(1/2,z,-2,2,theta,0,2*%pi))$

wxdraw3d(surface_hide = true,
color = "blue",proportional_axes=xyz,axis_3d = false,
xtics = none,ytics = none,ztics = none,
spherical(1,theta,0,2*%pi,phi,0,%pi),color=red,
cylindrical(1/2,z,-2,2,theta,0,2*%pi))$

U:log(sqrt((x+1)^2+y^2)) + log(sqrt((x-1)^2+y^2)) + 
log(sqrt((y+1)^2+x^2)) + log(sqrt((y-1)^2+x^2))$

wxdraw3d(xu_grid=50,yv_grid=50,explicit(U,x,-3/2,3/2,y,-3/2,3/2),
       contour_levels = 30,contour = map,surface_hide = true) ;

wxdraw3d(color = green,
       explicit(20*exp(-x^2-y^2)-10,x,0,2,y,-3,3),
       contour_levels = 15,contour = both,surface_hide = true) ;