A keystone in an arch's crown secures the other stones in place. Keystone species play the same role in many ecological communities by maintaining the structure and integrity of the community.

Miami-based Keystone Holdings Group proposes the 16-story Azul at Blue Lagoon building at 1200 Northwest 57th Avenue in unincorporated Miami-Dade County, according to Keystone’s application ...

The trough of the aquaduct could rest on the center and top of the arch, the keystone (red in the models). From there, the downward vertical force is modified partly into outward horizontal force, and ...

Keystone Linings is a leading manufacturer and supplier of perforated, slotted and patterned acoustics and decorative walls and ceilings linings. For over 40 years, Keystone Linings have specialised ...