Residential and commercial reconstruction in Greensburg, Kansas, which was destroyed more than two years ago by an unusually powerful tornado, have taken a green tack to address energy efficiency and other practical concerns. But the town’s push toward green also has enhanced its status as a showcase for various types of energy efficient residential construction.The recently concluded Chain of Eco-Homes Competition, a residential design contest co-sponsored by community nonprofit Greensburg GreenTown and open-source design firm FreeGreen, is among the latest sources of eco-boosterism in the town.Promoting eco-tourism in Greensburg is, after all, one of the goals of Greensburg GreenTown, a notion that didn’t seem lost on the firms and individuals who entered the competition. The contest attracted about 230 entries from professional and student designers, each focusing on one of three block-wall systems: lightweight, interlocking hollow blocks, made by German firm HIB, that are filled with blown-in insulation; Virginia Lime Works’ Enviro-Ment Masonry Unit, a lime-based masonry block that absorbs CO2 from the air; and U.K.-based Amvic Wall Systems’ insulating concrete forms.And the winners are …The first-place entry, Meadowlark House, by New York City-based Steven Learner Studio, is just under 1,450 square feet, features three bedrooms and two baths, and uses the HIB system, whose blocks stack Lego-style and are touted as being highly resistant (up to three stories) to earthquakes and hurricane-force winds.The top ranking earned Steven Learner Studios $10,000 in prize money and earned its Meadowlark House the right to be built in the GreenTown Chain of Eco-Homes, a 12-home project intended as a showcase for a variety of green construction strategies at different price levels. Construction on the house is expected to begin in November.Second place, and $1,000 in prize money, went to Stuttio Workshop, based on Venice, California. The firm’s Root/Breathe/Endure, a 1,900-sq.-ft. three-bedroom, two-bath home, is designed to use the Enviro-Ment Masonry system. Third place, and another $1,000, went to Daniel Day Studio, in Dallas, Texas, for its Linear Villa, a 1,492-sq.-ft. two-bedroom, two-bath home to be built using the Amvic ICFs.Because they are among the three contest winners, both Root/Breathe/Endure and Linear Villa are, like Meadowlark House, eligible for construction as part of the 12-home Chain of Eco-Homes, provided enough money can be raised to get them in the ground. At this point, Chain of Eco-Homes’ lineup includes the University of Colorado’s winning home from the 2005 Solar Decathlon and the concrete Eco-Home Silo, which opened to the public in May.The contest’s eight-judge panel included modular-design architect Michelle Kaufmann and Steve Thomas, current host of the Discovery Channel’s Renovation Nation and former host of This Old House on PBS.