Let's start by understanding a common pattern in the code for Curve v1. We can see that the functions `exchange`, `add_liquidity`, and the `remove_liquidity` functions are called on the StableSwap3Pool contract. The pattern we'll see in all the functions is that they first calculate the `A` parameter, and then they calculate the liquidity `D`. Let's examine the `exchange` function. We can see that it first normalizes the token balances, transfers the token in, updates the token balance, and then calculates the token out balance. After that, it calculates the `A` parameter, the liquidity `D`, calculates the token out, calculates the swap fee, updates the token balances, and then transfers the token out. The `add_liquidity` function has a similar pattern. It calculates an imbalance fee multiplier, calculates `A`, calculates the liquidity `D0`, transfers the tokens in, updates the token balances, calculates liquidity `D1`, calculates the imbalance fee, calculates liquidity `D2`, updates the token balances, calculates the liquidity provider shares, and then mints the liquidity provider's LP shares. The `remove_liquidity` function is a little different. It first calculates the token out amounts, updates the token balances, and then transfers the tokens out. Finally, it burns the LP shares. The `remove_liquidity_one_coin` function first calculates `dy` and the imbalance fee, calculates `A`, calculates `D`, calculates the imbalance fee, updates the token balances, burns the LP shares, and then transfers the token out. So, why do we see a pattern of calculating the `A` parameter before calculating the liquidity `D`? We can see that the `A` parameter is a fixed number, but an admin can decide to set a new `A` parameter. Over time, as the `A` parameter changes, the liquidity `D` will also change. Let's take a look at an example graph of Curve v1's equation. In this graph, we are looking at the equation for two tokens. We can see that the `x0` and `y0` values must be on this curve. This curve will adjust as tokens are swapped. For example, if token `x` goes out and token `y` comes in, the point will move up and to the left. Conversely, if token `x` comes in and token `y` goes out, the point will move down and to the right. Let's now see what happens when the `A` parameter changes. In this graph, we can see that the current token balance is represented by a blue dot. An admin could decide to update the `A` parameter to a higher number. We can see that the token balance is no longer on the curve. To get the blue dot back on the curve, we need to change the liquidity `D` so that the curve will go through the token balances. We see, then, that the code first calculates the `A` parameter and then calculates the `D` parameter. This is because the code needs to find the liquidity `D` that will satisfy the equation given the `A` parameter and the token balances.