i got this example:

http://img405.imageshack.us/img405/2299/64500275qt5.gif

i got a sequence of numbers

i cant understand from where they conclude that the limits of every sub sequence is {2,1,0,-1}

there are no sub sequences pointed out

there are no formulas for each sub sequence

how did they came with

that the limits of every sub sequence is {2,1,0,-1}

??