Kilit Taşı is a multidiciplinary design firm, specialized in industrial design, interiors and architecture.
keystone (noun) /kee-stohn/
('kilit taşı' means 'keystone' in english)
1. the middle stone in the top of an arch which has a special shape and holds all the other stones in position
2. the most important part of a plan, idea, etc. on which everything else depends