# Fitzhugh-Nagumo
dv/dt = f(v)-w+I_0
dw/dt = eps*(v-gamma*w)
f(v)=v*(1-v)*(v-a)
param a=.25,eps=.05,gamma=1,I_0=.25
@ total=100,dt=.2,xhi=100
@ nplot=2,xp2=t,yp2=w
done