Check-kiting example

Sally opens checking accounts at Bank A and Bank B. Initially, she deposits $500 in Bank A and $0 in Bank B. She then writes a $10,000 check on her account at Bank A and deposits it in Bank B. Unaware that Sally has insufficient funds in her account at Bank A, Bank B immediately gives her credit on her account. During the three business days it takes Bank B to clear the check on her account at Bank A, Sally writes a $10,000 check on her account at Bank B and deposits it in Bank A to cover her first $10,000 check. Bank A immediately gives her credit on her account, and Bank B clears Sally's first $10,000 check. 

Sally continues writing bad checks between her accounts. By doing so, she illegally obtains a $10,000 interest-free loan.