It’s alive: Bob Seng builds a wall out of Jell-O on Thursday at the Seattle Center in Seattle. The jiggly wall, which stands about 5 feet high and 12 feet long, is the work of artists Seng and Lisa Hein, who were commissioned for a three-week evolving exhibit to celebrate the 50th anniversary of the 1962 Seattle World’s Fair. The pair will be adding rows of loaf-size Jell-O bricks through next Saturday for the Big Birthday Bash. The artists cook up the gelatin on a hot plate and cool it in molds in a refrigerator on the site. Blueberry, raspberry, orange, cherry and blackberry bricks are held in place by a gypsum mortar that supports the wall as the Jell-O on the bottom melts.