To understand how this works, let us use an ETH/USDT liquidity pool as a case study. When ETH is purchased by traders, they add USDT to the pool and remove ETH from it. This causes the amount of ETH in the pool to fall, which, in turn, causes the price of ETH to increase in order to fulfill the balancing effect of x*y=k. In contrast, because more USDT has been added to the pool, the price of USDT decreases. When USDT is purchased, the reverse is the case – the price of ETH falls in the pool while the price of USDT rises.