How to plot biorhythm

The following script plot the biorhythm of a person born in 14/3/1988 in a range of 20 days.

from datetime import date
import matplotlib.dates
from pylab import *
from numpy import array,sin,pi

t0 = date(1988,3,14).toordinal()
t1 = date.today().toordinal()
t = array(range((t1-10),(t1+10))) # range of 20 days

y = 100*[sin(2*pi*(t-t0)/23),  # Physical
         sin(2*pi*(t-t0)/28),  # Emotional
         sin(2*pi*(t-t0)/33)]; # Intellectual

# converting ordinals to date
label = []
for p in t:
 label.append(date.fromordinal(p))

fig = figure()
ax = fig.gca()
plot(label,y[0],label,y[1],label,y[2])
# adding a legend
legend(['Physical', 'Emotional', 'Intellectual'])
# formatting the dates on the x axis
ax.xaxis.set_major_formatter(matplotlib.dates.DateFormatter('%d/%b'))

show()

The resulting graph: