What does this childish scribble of a drawing represent?
UPDATE: Steve Hatton needed only seven minutes to get this one. These lines represent the redesign of de Maisonneuve Blvd. between St. Laurent and St. Urbain.
As of a few months ago, drivers (and cyclists) heading west no longer have a gradual curve that takes them around Place des Arts, but rather a stop sign and hard right onto Clark before they turn left back onto de Maisonneuve. This new layout gives more space for building construction nearby, but also reduces the speed of traffic.
In order to accommodate all the cars, the direction of Clark (a one-way street) is reversed between de Maisonneuve and ... uhh ... de Maisonneuve. This effectively reserves that stretch of road for drivers heading west on de Maisonneuve.
A little history
The path of de Maisonneuve Blvd. in this area is a bit strange, particularly because it curves upward to run right next to Ontario St. The path is entirely a result of the path of the green line of the metro between St. Laurent and Place des Arts stations. Before the metro's construction, de Maisonneuve Blvd. didn't exist. What we now know as that boulevard was a handful of unconnected roads, including de Montigny St. (everything east of St. Laurent), the last bit of which (the lower red portion in the image at top) has been removed with this redesign.
UPDATE (June 9): It's been pointed out below that a tiny stretch of de Montigny still exists, between Clark and St. Urbain, under this new design.