It would just keep calling itself forever, and never get anywhere and what they key with recursion is that it can call itself as long as every time it calls itself it's making its way down to the base cases so at some point if it keeps calling itself, it keeps calling itself eventually it's able to build back those calls to get back to the base cases and then recontruct what the original value was from that and that's why its working each call to fibonacci is a simpler version