interleave.py

import eventlet

def foo(name):
    for i in range(3):
        print "foo(%s): i=%d" % (name, i)
        eventlet.sleep()
    
f1 = eventlet.spawn(foo, 'A')
f2 = eventlet.spawn(foo, 'B')

for i in range(3):
    print "main:   i=%d" % i
    eventlet.sleep()

f1.wait()
f2.wait()