Provide an address in config.txt, run random-postcard and get a 6 x 4 inch postcard with a random bar chart on the backside.
go get -u github.com/spaghettisandwich/random-postcard
From the random-postcard directory
# edit the address in config
vim config.txt
# run random-postcard
./random-postcard
# open it!
open random-postcard.pdf
If you don't have Go installed you can download the binary and run from command line in Mac or "double-click" the random-postcard.exe in Windows