Start3d(); Putaxes3d(4); Xyzax3data("","x=[-5,5]","y=[-5,5]","z=[-2,6]"); fd=[ "p", "x=R*cos(T)","y=R*sin(T)","z=2.5*(2-R)", "R=[0,2]","T=[0,2*pi]","e" ]; if(Isangle(), Sf3data("1",fd); , Startsurf(); Sfbdparadata("1",fd); Crvsfparadata("1","ax3d","sfbd3d1",fd); Sfcutparadata("1",["z=x-y","z=x-y+1"],"sfbd3d1",fd,["Color=blue"]); if(Gccexists(), ExeccmdC("1",[""]); ); ); Windispg();