(time-of-day 0) -> midnight
(time-of-day 1440) -> midnight
(time-of-day 2880) -> midnight
(time-of-day 4320) -> midnight

(time-of-day 720) -> noon
(time-of-day 2160) -> noon

(time-of-day 1) -> ("12:01" am)
(time-of-day 1441) -> ("12:01" am)
(time-of-day 11) -> ("12:11" am)
(time-of-day 60) -> ("1:00" am)
(time-of-day 61) -> ("1:01" am)
(time-of-day 185) -> ("3:05" am)
(time-of-day 719) -> ("11:59" am)

(time-of-day 721) -> ("12:01" pm)
(time-of-day 2161) -> ("12:01" pm)
(time-of-day 730) -> ("12:10" pm)
(time-of-day 780) -> ("1:00" pm)
(time-of-day 1439) -> ("11:59" pm)