>	with(plots):surface:=plot3d(9-y^2-x^2,x=-2.5..2.5,y=-0.5..2.5,view=-4..10,axes=boxed,orientation=[100,70]):

>	plane:=plot3d(-4,x=-2.5..2.5,y=-0.5..2.5,view=-4..10,axes=boxed,orientation=[100,70]):

>	B1:=spacecurve([2.5,-0.5+t,-4,t=0..3],color=blue,thickness=3):

>	B2:=spacecurve([1.5,-0.5+t,-4,t=0..3],color=blue,thickness=3):

>	B3:=spacecurve([0.5,-0.5+t,-4,t=0..3],color=blue,thickness=3):

>	B4:=spacecurve([-0.5,-0.5+t,-4,t=0..3],color=blue,thickness=3):

>	B5:=spacecurve([-1.5,-0.5+t,-4,t=0..3],color=blue,thickness=3):

>	B6:=spacecurve([-2.5,-0.5+t,-4,t=0..3],color=blue,thickness=3):

>	B7:=spacecurve([-2.5+t,-0.5,-4,t=0..5],color=blue,thickness=3):

>	B8:=spacecurve([-2.5+t,0.5,-4,t=0..5],color=blue,thickness=3):

>	B9:=spacecurve([-2.5+t,1.5,-4,t=0..5],color=blue,thickness=3):

>	B10:=spacecurve([-2.5+t,2.5,-4,t=0..5],color=blue,thickness=3):

>	H9:=spacecurve([-1,1,-4+t,t=0..11],color=red,thickness=3):

>	Tnplane7:=plot3d(11+2*x-2*y,x=-1.5..-0.5,y=0.5..1.5,view=-3..10,axes=boxed,orientation=[100,70]):

>	SurfPt1:=pointplot3d([-1,1,-3.99],symbol=cross,symbolsize=50,color=red):

>	SurfPt2:=pointplot3d([-1,1,7],symbol=cross,symbolsize=50,color=red):

>	vector1:=arrow(<-1.5,0.5,7>,<1,0,2>,width=[0.03,relative],color=red,thickness=3):

>	vector2:=arrow(<-1.5,0.5,7>,<0,1,-2>,width=[0.03,relative],color=red,thickness=3):

>	display(surface,plane,B1,B2,B3,B4,B5,B6,B7,B8,B9,B10,H9,Tnplane7,SurfPt1,SurfPt2,vector1,vector2);

>	surface:=plot3d(9-y^2-x^2,x=-2..0,y=0..2,view=4..10,axes=boxed,orientation=[100,70]):

>	Tnplane7:=plot3d(11+2*x-2*y,x=-1.5..-0.5,y=0.5..1.5,view=4..10,axes=boxed,orientation=[100,70]):

>	SurfPt2:=pointplot3d([-1,1,7],symbol=cross,symbolsize=50,color=red):

>	vector1:=arrow(<-1.5,0.5,7>,<1,0,2>,width=[0.03,relative],color=red,thickness=3):

>	vector2:=arrow(<-1.5,0.5,7>,<0,1,-2>,width=[0.03,relative],color=red,thickness=3):

>	display(surface,Tnplane7,SurfPt2,vector1,vector2);

>	surface:=plot3d(9-y^2-x^2,x=-1.5..-0.5,y=0.5..1.5,view=4.4..9.2,axes=boxed,orientation=[100,70]):

>	Tnplane7:=plot3d(11+2*x-2*y,x=-1.5..-0.5,y=0.5..1.5,view=4.4..9.2,axes=boxed,orientation=[100,70]):

>	SurfPt2:=pointplot3d([-1,1,7],symbol=cross,symbolsize=50,color=red):

>	vector1:=arrow(<-1.5,0.5,7>,<1,0,2>,width=[0.03,relative],color=red,thickness=3):

>	vector2:=arrow(<-1.5,0.5,7>,<0,1,-2>,width=[0.03,relative],color=red,thickness=3):

>	display(surface,Tnplane7,SurfPt2,vector1,vector2);

>	surface:=plot3d(9-y^2-x^2,x=-1.3..-0.7,y=0.7..1.3,view=5.6..8.4,axes=boxed,orientation=[100,70]):

>	Tnplane7:=plot3d(11+2*x-2*y,x=-1.3..-0.7,y=0.7..1.3,view=5.6..8.4,axes=boxed,orientation=[100,70]):

>	SurfPt2:=pointplot3d([-1,1,7],symbol=cross,symbolsize=50,color=red):

>	display(surface,Tnplane7,SurfPt2);

>	surface:=plot3d(9-y^2-x^2,x=-1.1..-0.9,y=0.9..1.1,view=6.5..7.5,axes=boxed,orientation=[100,70]):

>	Tnplane7:=plot3d(11+2*x-2*y,x=-1.1..-0.9,y=0.9..1.1,view=6.5..7.5,axes=boxed,orientation=[100,70]):

>	SurfPt2:=pointplot3d([-1,1,7],symbol=cross,symbolsize=50,color=red):

>	display(surface,Tnplane7,SurfPt2);

>	surface:=plot3d(9-y^2-x^2,x=-1.05..-0.95,y=0.95..1.05,view=6.8..7.2,axes=boxed,orientation=[100,70]):

>	Tnplane7:=plot3d(11+2*x-2*y,x=-1.05..-0.95,y=0.95..1.05,view=6.8..7.2,axes=boxed,orientation=[100,70]):

>	SurfPt2:=pointplot3d([-1,1,7],symbol=cross,symbolsize=50,color=red):

>	display(surface,Tnplane7,SurfPt2);

>