The "triennial cycle" was the practice of Jews in Eretz Yisrael, which works by dividing the Torah into weekly sections, roughly a third of the length of a Babylonian weekly parsha, which, if you follow it week by week, means you end up finishing in something like three and a half years. The revived triennial cycle is now on its second run ב''ה with Jews around the world learning according to its schedule.
Shemot Sidrah 14 - שמות סדרה יד
Shemot 18:1 - 19:8 - שמות טז:כח - יח:א -יט:ח
Haftara: Yishayahu 33:13 - 34:8 - ישעיהו לג:יג - לד:ח
Resources
Suggested aliyot divisions for Bereshit