However, early Netherlandish painting in the 15th century was the first to make oil the usual painting medium, and explore the use of layers and glazes, followed by the rest of Northern Europe, and only then Italy.
An American flag or for that matter any flag flown upside-down is considered a sign of distress... US Code:T36 Ch10.176. (a) The flag should never be displayed with the union down, except as a signal of dire distress in instances of extreme danger to life or property.
A blue flag with a white stripe down the middle signals that the boat is carrying dangerous cargo and is on fire. A boat or ship with a yellow flag that has a blue stripe down the middle is having difficulty steering. A flag made up of a red triangle and a yellow triangle signals that there is a man overboard.