In partnership since the late-1970s, Ken Yeang and Tengku Robert Hamzah have built up a reputation for projects that are ecological, bioclimatic and energy efficient. Ken Yeang examines how the practice appoaches their design and planning work. Best known for its 'eco' skyscrapers, the practice's recent work has involved low-rise and medium-rise buildings, on and under the ground - 'groundscrapers' and 'subscrapers'. These projects respond to the local climate and to the ecological considerations of the site: where possible, they are designed to be mimetic ecosystems.