The cup is receiving's vessel — what holds what is poured for you. The empty cup awaits; the overflowing cup exceeds capacity or blesses beyond it; the broken cup can no longer receive. My cup runneth over is abundance; the empty cup, depletion or readiness.
Positive Resonance
Capacity to receive, the filled vessel, abundance held
Shadow Aspect
The cracked vessel, poured for and unable to hold, the empty cup unfilled