Assembling the wing from thousands of tiny identical pieces could make aircraft lighter and more energy efficient. How it works: The wing is made from an open, lightweight lattice framework that is covered with a thin layer of polymer material. It looks like thousands of matchstick-type struts welded together in small triangle shapes.

Protesters in Iran are demanding that Supreme Leader Ayatollah Ali Khamenei steps down, after the country's military admitted to accidentally downing a Ukrainian passenger jet, killing all 176 people on board. Ukraine International Airlines flight PS752 crashed shortly after leaving Imam Khomeini International Airport in the Iranian capital of Tehran on Wednesday.