朋

Left half - visually identical to 月 moon, but historically one of two strings of cowrie shells once used as currency. Two such strings hung side by side meant a matched pair, the original picture for 'companion, friend.' Later assigned the moon radical for indexing, which is why it sits beside 期 and 望.

Right half - the second cowrie-string, mirrored against its partner. The doubling is the whole point: a pair makes the picture. From two strings of equal worth came the meaning of 'paired companion, friend of equal standing,' still alive in modern 朋友 friend. A textbook compound ideograph relying entirely on reduplication.