option tstart = 0.0, tstop = 40, outstep = -0.1

var x=0.0 delay scale=0.0, v=1.0
param mu=3.5, tau=2.0

aux E = (x*x + v*v)/2

x'= v
v'= mu*(1 - x*x)*v - x(t-tau)

// print to "oscillator.lst" t, x, v, E
print t,x,v
plot x,v