echo_client_tulip.py

import asyncio

END = b'Bye-bye!\n'

@asyncio.coroutine
def echo_client():
    reader, writer = yield from asyncio.open_connection('localhost', 8000)
    writer.write(b'Hello, world\n')
    writer.write(b'What a fine day it is.\n')
    writer.write(END)
    while True:
        line = yield from reader.readline()
        print('received:', line)
        if line == END or not line:
            break
    writer.close()

loop = asyncio.get_event_loop()
loop.run_until_complete(echo_client())

echo_server_tulip.py

import asyncio

@asyncio.coroutine
def echo_server():
    yield from asyncio.start_server(handle_connection, 'localhost', 8000)

@asyncio.coroutine
def handle_connection(reader, writer):
    while True:
        data = yield from reader.read(8192)
        if not data:
            break
        writer.write(data)

loop = asyncio.get_event_loop()
loop.run_until_complete(echo_server())
loop.run_forever()

(This is in response to https://gist.github.com/denik/8c4fcf4593ced686c718 from https://twitter.com/gevent/status/462617361821220864)