Which window design has numerous pieces of adjustable glass sections that overlap when closed?

The window design characterized by numerous pieces of adjustable glass sections that overlap when closed is the jalousie window. This type of window features slats of glass or sometimes other materials that can be angled open to allow for ventilation while still providing privacy and protection from the elements.

Jalousie windows are especially useful in providing airflow control and can be adjusted to let in light and air while minimizing direct rain. When the slats are closed, they overlap to create a barrier against the outside environment, which enhances insulation and security. The unique functionality of overlapping slats allows for a customizable level of openness, making this design particularly advantageous in hot climates where ventilation is needed.

Other types of windows, such as awnings, double hung, and projected windows, do not utilize the overlapping slat design and primarily feature solid panels or frames, which serve different operational and aesthetic purposes.