Originally published on Medium in 2020, republished here as I move my writing to my own site.

In April, at the start of Covid lockdown, I found time to create this mural out of 2650 Post-It Notes.

Finished Post-it Note mural of Seattle

In case you aren’t familiar with the area or just don’t recognize it right away, the mural is a map of Seattle. Here is the source image:

Source map of Seattle

First I blocked this image into post-it note sized sections, averaging the colors in each section:

Image blocked into post-it note sections

Then I used K-Means clustering to find 5 colors that are good enough to draw the whole image with:

K-Means color clusters

Then I mapped these 5 colors to the 5 post-it note colors that I had to produce the final image:

Final color-mapped image

I spit this out into a csv template that I copied on my wall. Creating the template for this was a fun merging of algorithms and art. Putting the actual post-it notes on the wall was hours of boring work that I wouldn’t wish upon anyone.

The code is not super clean but it can be found here: chaltonj/PostItWall