AITA for putting a coloring page on my neighbor’s windshield?

I (F24) just recently moved in with my boyfriend (M25), his roommate (F28). We live in a multi-unit building that has a shared carport, each unit with an assigned spot. Each section of the car port can hold 2 cars, with a support beam on either side. Even before I moved in, the downstairs neighbor has always parked toward the center of the 2 parking spots, one being hers, and one being ours. It wasn’t a problem prior to my moving in because my roommate drives a moped. I, however, drive a medium-sized SUV, as does our neighbor.
Since I have moved in, our neighbor continues to park in the middle of the carport, making it difficult for me to park correctly. I have to park so close to the support pole that passengers cannot get into my car on the passenger side unless I back out of the spot first. We have tried talking to her, texting her, texting the landlord, literally everything. 2 weeks ago, neighbor was parked so bad my roommate could not pull her moped into the spot. (I leave room in front of my car so roommate can pull between the wall and my hood). My roommate asked her to move, she came down and stated that she would not move her car and that it’s not her problem because she’s “on her side”. (The rear half of her car was on our side).
We did an experiment, and my roommate parked her moped somewhere else for a week. Neighbor, parked straight as a metal pole. Roommate moved her moped back, neighbor is crooked again. Today I got home and could barely pull in without hitting the neighbor’s car.
I printed out a witty coloring page and placed it under the neighbor’s windshield wiper. It’s a B/W picture of a cartoon turtle, urging the reader to practice coloring to improve their parking. We have tried everything and she is so mean to my roommate every time we ask her to move.

Did I take it too far, or is this justified?