RHY.8:4.2 - Choose a construction whose effect is understandable

Choose an operation from the rhythmic material and the intended change.

Wanted change	Construction	Relations to examine after the change
Enter at a different place in a cycle	Add a displacement to each selected occurrence and reduce positions modulo the cycle length. Move associated duration and sound labels with the occurrence when that is the intended transformation.	Entry cue, phase relative to other layers, and material crossing the cycle boundary.
Expand or compress a phrase	Scale its durations, or add/remove a specified part of each repeated statement; recompute the phrase’s total span.	Tempo, internal articulation, available action intervals and its fit with adjoining material.
Make a repeated ending reach a chosen point	Choose statement and intervening-gap durations, calculate the whole ending and work backward from its endpoint. Adjust the setup by the corresponding amount.	The convention for the final articulation, the maintained reference and the available preceding material.
Distribute a given number of attacks over a cycle	Choose an arrangement, such as an evenly distributed seed, then retain the phase and articulations needed by this use.	Minimum intervals, entry, accent and the intended style; evenness is one construction choice.
Change the articulation of a continuous contribution	Reposition or reshape its marked changes while retaining the required trajectory, support or sounding contribution.	Continuity, available movement or control rates, usable timing and the state needed for continuation.
Build a larger passage from familiar parts	Concatenate, overlap or alternate parts under explicit timing and allocation relations.	Boundary transitions, simultaneous demands and the whole passage’s intended development.

A named tradition can supply a more specific construction. In Nelson’s treatment of a mōrā, three statements are separated by two equal-duration gaps. A gap can include sound; it is a structural separation, not a synonym for silence. A kōrvai can build a larger, shaped composition whose closing portion is a mōrā. Use the learned phrase grammar and setting when constructing either, rather than treating the names as labels for arbitrary repetition.

For the simple equal-statement case, let s be the statement’s duration and g each gap’s duration, measured in the same pulse unit. The total is D = 3s + 2g. If T is the boundary after the final statement, the start is T − D. A last attack, the completion of its duration and a later arrival accent are different possible targets; select the one actually required.