fib
	"returns the fibonacci value of myself
	by Nathan Wallace. Started April 17, 2007"
	(self = 0)
	ifTrue: [^ 0]
	ifFalse:[	(self = 1)
			ifTrue: [^ 1]
			ifFalse:[(self >= 2)
				ifTrue:[	^(((self - 1) fib) + ((self - 2) fib))]
				ifFalse:[^-1]]]
		
	"Example Run:
	Command: 0 fib.
	Result: 0
	Command: 1 fib.
	Result: 1
	Command: 2 fib.
	Result: 1
	Command: 25 fib.
	Result: 75025"! !