During the design of a fact table, what is the difference between an 'accumulating snapshot' and a 'periodic snapshot' regarding how they track time-based business metrics?

A periodic snapshot fact table captures the state of a business process at regular, consistent intervals of time. It acts like a recurring status report, recording metrics such as daily account balances, monthly sales totals, or weekly inventory levels. Each row represents a summary of activity over a specific time period, such as a day, week, or month, ....