Visualize a roulette wheel. It has 36 numbers, alternating odd and even, black and red.
Spin the wheel. Now introduce a marble propelled along the edge of the bowl that houses the wheel, but in the opposite direction of the spin.
Slowly, the ball will lose momentum and drift downward in its orbit until it collides with the wheel spinning contrarily. The marble jumps and wanders randomly until it finally settles on one number as the wheel drags to a halt. That then becomes the issue of the day, or hour.