A bank transfer and a Solana swap do different jobs
Week 2 of the Foundations Circle separates a bank payment from a pool swap, including the SOL fee and the gap called slippage.
A bank transfer asks an institution that already holds both accounts to change two balances. The customer writes an amount, the bank checks the account, and a receipt follows. People who arrive at the Paju reading room often expect a Solana swap to feel like that receipt with a new logo.
A swap asks a program to exchange one token for another. On Solana, many swaps trade against a pool: two piles of tokens sitting in a program, with a price implied by how large each pile is. If someone adds a lot of token A, the program gives token B according to that ratio, and the ratio itself moves. The circle's paper example uses a pool of 100 and 100 so the arithmetic stays visible.
The network fee is a separate line. A Solana transaction pays a fee in SOL to be included. That fee is not the price of the token being bought. Readers write the two numbers in different columns so they stop adding them together.
Slippage is the gap between the figure shown before signing and the figure after the trade lands. A pool can move because someone else's swap arrived first. Week 2 names that gap and stops there. The room does not place a trade, and readers are not asked to open a position.
If you want the same example with a facilitator watching your notes, the Foundations Circle spends a full Tuesday on it. A single stuck page fits a desk appointment instead.