Kindness of strangers

Came across this super sweet poster this morning at the corner of 18th and Mission streets. Not sure who is behind it but according to the description posted next to it, it came out of a project where 1,000 people were asked to write a kind note to a stranger. Half are pasted around San Francisco; half are “circulating” around the city.

Seen any of these posters or notes elsewhere? Know more about the project? Tell me more.