There are known knowns Former US Secretary of Defense, Donald Rumsfeld, famously popularized the phrase "known knowns." Here we're going to distill his remarks into a four-line stanza.

Specifically, output this text:

known knowns
known unknowns
unknown knowns
unknown unknowns


Capitalization doesn't matter (for example, Known unKnowns is fine), and a single trailing newline is acceptable, but no other formatting changes are allowed. That means a single space between the words, and either LF (59 bytes) or CR/LF (62 bytes) between the lines.

Rules


Either a full program or a function are acceptable. If a function, you can return the output rather than printing it.
Standard loopholes are forbidden.
This is code-golf so all usual golfing rules apply, and the shortest code (in bytes) wins.
Python 2, 54 52 bytes

-2 bytes thanks to xnor


k='unknowns'
for i in 8,6,2,0:print k[i/3:7],k[i%3:]


Try it online!

The results from the / and % will be [[2, 2], [2, 0], [0, 2], [0, 0]] that will be the starting indexes, removing the un when 2, keeping the string unaltered when 0