These are not standard windows. Each window in this building was selected based on its orientation to maximize comfort and energy performance throughout the year.

South-facing windows are designed to admit more solar heat in winter when the sun sits lower in the sky. North- and east-facing windows use higher thermal resistance glazing to reduce heat loss during cold weather and limit overheating during summer.
The result is a building that uses the sun itself as a heat source half the year, and shields itself from it the other half, without active controls.