+--+ | | +--+ / \ / \ / \ / \ / \ / \ / \ / \ +--+ +--+ | | | | +--+ +--+ /|\ /| / | \ / | / | \ / | / | \ / | / | \ / | / | \ / | / | \ / | / | \ / | +--+ +--+ +--+ +--+ | | | | | | | | +--+ +--+ +--+ +--+Using the digits from 1 to 9 exactly once, construct 7 positive integers so that each positive integer is equal to the sum of the positive integers in the squares that are connected to it from below. Some of these seven positive integers can contain more than one digit.