Those walking along Canal Street might have noticed something out of the ordinary of late. No, not whatever impromptu one-person show is happening on the street. We’re talking about Post-it notes. New York 1 first reported on the conflagration as it started at one window and quickly spread to the entire block. Some of the designs, which range from simple text messages to complicated pop culture references, are super creative.Of course, they were all posted to Twitter.It all started May 9, when two creative agencies began exchanging messages across the way. Havas Worldwide and Horizon Media quickly saw their little prank war get out of hand. But they’re loving the spirited communication."It was a nice return to the world of analog communications — becoming a fun and organic way for us to communicate with our neighbors and further fuel our agency culture of collaboration," a Havas spokeswoman told DNAinfo New York in an email. "But given we're in the creative business, this was not enough."Here are some of the best posts to Twitter.