restart:with(DEtools):sigma:=10.0:B:=8/3.: R:=28.:
 Lorenz:={D(x)(t)=sigma*(y(t)-x(t)),
 D(y)(t)=R*x(t)-y(t)-x(t)*z(t),
 D(z)(t)=-B*z(t)+x(t)*y(t)};

 DEplot3d(Lorenz,{x(t),y(t),z(t)},t=0..20.,
 [[x(0)=10,y(0)=10,z(0)=20]],scene=[x(t),y(t),z(t)],
 stepsize=.011,title=`Lorenz Attractor`,linecolour=blue)