Actually, in tennis, 3 and 4 are dropped in randomly into different halves. So either 1 v 3 and 2 v 4 or 1 v 4 and 2 v 3 is possible. In a pure snake seed, it is 1 v 4 and 2 v 3. In the random version, only 1 and 2 are not in the same half. 3 and 4 are randomly put into different halves...