fibo := [ :f :o :c :k | | e f1 f2 f3| "f1: term Fn, f2: term Fn+1, o & c: origin and center of the arc e: extremity of the arc/orgin of the next arc" f1 := f first. f2 := f second. f3 := f1 + f2. e := shape value: c value: o value: f2. c := canvas scale: c center: e factor: f3 / f2. k > 0 ifTrue: [ fibo value: {f2. f3} value: e value: c value: k - 1 ]].