Rigveda 10.166.5

यो॒ग॒क्षे॒मं व॑ आ॒दाया॒ऽहं भू॑यासमुत्त॒म आ वो॑ मू॒र्धान॑मक्रमीम् ।अ॒ध॒स्प॒दान्म॒ उद्व॑दत म॒ण्डूका॑ इवोद॒कान्म॒ण्डूका॑ उद॒कादि॑व॥

yogakṣemaṃ va ādāyā'haṃ bhūyāsamuttama ā vo mūrdhānamakramīm |adhaspadānma udvadata maṇḍūkā ivodakānmaṇḍūkā udakādiva ||

Our plain-language meaning of this verse is waiting for scholar review.