The three-coin method
Throw three coins six times. Heads count as 3 and tails as 2. Add each throw to obtain 6, 7, 8 or 9. The first throw is the bottom line and the sixth is the top line.
6 is changing yin; 7 is yang; 8 is yin; 9 is changing yang. Digital throws use independent random bits from your browser. Your question does not choose the result.