Wǒ ài nǐ means “I love you”.
You bring your wife a present and ask where to put it. She points to an apple lying on a trampoline at the back: the “where” (wo in German) and the apple give you wǒ, and the trampoline gives you the tone that falls and rises again. The present itself is an egg with a sharp point at one end – egg (Ei in German) and pointed give you ài, falling. And above the whole scene hangs a picture of the Nile flowing softly along: nǐ.
The Nile comes up twice more in this training – always for the same syllable.