R, 52 51 50 bytes

cat(gsub(1,"known","1 1s
1 un1s
un1 1s
un1 un1s"))

Try it online!

Surprisingly short substitution and print commands make this an actually competitive R answer in a string challenge!

Even if it's super boring. Mildly more interesting now, and with a byte saved thanks to J.Doe!

Saved another byte thanks to this answer, also by J.Doe!