STEELWORKERS TACK-WELD part of the skeleton into place Thursday for the new Unitarian Universalist Church at Pleasant and Middle streets in Brunswick. A vertical row of windows will fit inside the frame, catching the afternoon sun to form a west-facing “tower of light,” according to UUC personnel. A corresponding column of windows will be installed on the east-facing wall. Because of a uniquely angled roofline, the two “towers” will combine to help funnel natural light into the sanctuary and narthex of the new church. “It’s a way to get natural light into the middle rooms of the building, which have no windows,” said Mike Heath, chairman of the church’s board of directors. The $1.8 million, 8,600-square-foot building will replace the former church building that burned in 2011.