Moon blocks — jiaobei, crescent-shaped wooden or bamboo blocks — are a folk ritual common in Fujian, Taiwan and southern China. A pair is cast and read by how the flat and rounded sides land: a "yes-no" answer, a "laughing" answer or a "negative" answer. It is a cultural communication ritual and a way of settling the mind.
One block flat-side up and one rounded-side up is traditionally called a "sacred" or affirmative answer — read as a response that confirms your intention and encourages you to proceed with a steady mind.
Two flat sides up is the "laughing" answer, traditionally read as "smile and think again" — a reminder to phrase your question more concretely.
Two rounded sides up is the "negative" answer, traditionally taken as a hint that the timing or the approach may not be right yet — steady yourself and slow down.