```
## A trivial (but inefficient!) example:
fib <- function(n)
if(n<=2) { if(n>=0) 1 else 0 } else Recall(n-1) + Recall(n-2)
fibonacci <- fib; rm(fib)
## renaming wouldn't work without Recall
fibonacci(10) # 55
```

Run the code above in your browser using DataLab