Both space and time are loops and trees. Loop means it is a closed region of space and time. An example of a closed region of space is a house, and an example of a closed region of time is an hour. The hierarchy is that a house is inside and a city and an hour is inside a day.
A more correct way to think about it is a house is a “unit” of space and an hour is a “unit” of time. Therefore, even though space and time can be subdivided we can understand in terms of larger units. Without these units, “hour” and “house” would not be individually meaningful; we would reduce these units always to smaller and smaller units in a reductionist theory.
One consequence of this hierarchy of space and time is the uncertainty relations in atomic theory. The atomic particle’s time is said to be “uncertain” because it is spread in time. Just like you can say that the year is 2018 but the year is not yet completely finished. Similarly, I can say that I’m in a city but I’m outside my house. There is hence a distinction between a position state and a classical position. The position state is like being in the house, and the classical position is like being in a particular room of the house. Atomic theory speaks about the position state which is certain, but the classical position is uncertain. However, experiments have shown that we can fix the position state to an ever-increasing degree of certainty, which is like saying that after I fix my position as being in the house, I can further fix the position of being in a room.
The hierarchical position and time are needed because of meanings. Just like you can say that the time is half past 12, but you haven’t said which day we are talking about. Similarly, you can say that I’m in the bedroom, but you haven’t said which specific house I’m in. So ‘bedroom’ is not universally meaningful; it is meaningful in relation to a particular house. Likewise, half past 12 is not meaningful universally; it is meaningful in relation to the particular day. The day is meaningful in relation to the month, the month in relation to the year, etc.
So, what we call the ‘cycle’ of time is actually a unit of time like a day that begins and ends, and the hierarchy of time is that the day is inside a month, which is inside a year, etc.