© Hong Yi / Oh I See Red

When you ditch the car for a bike, you're contributing to the health of the planet and all its inhabitants -- but how often does someone take the time to thank you?

To express her gratitude to cyclists in Melbourne, artist and architect Hong Yi, went around the city attaching thank you notes to bikes, reading "Thank you for saving the world...with one less car!!!"

© Hong Yi / Oh I See Red

On her blog Oh I See Red, Yi, who moved to Melbourne from Shanghai for a job, writes that she was impressed by the city's efforts to promote cycling:

Another thing I love about Melbourne is how cycle-friendly this city is! I'm so glad Melbourne has now implemented a city-wide bike hire scheme, encouraging Melburnians to cycle as a convenient and sustainable form of transport.

I came up with another streetart project -- I hung little tags onto bikes to show how glad I am that people are choosing to cycle. All hand-written make it all feel a little more personal!

What a nice idea -- I can only hope that someone will come to New York and do the same for me someday!

© Hong Yi / Oh I See Red