Spirals

We will now draw our first recursive function with the turtle. The goal is to draw different kind of spirals with the same function, which prototype is the following:
[!java]void [/!]spiral([!java]int [/!]steps[!scala]:Int[/!], [!java]int [/!]angle[!scala]:Int[/!], [!java]int [/!]length[!scala]:Int[/!], [!java]int [/!]increment[!scala]:Int[/!])
To help you understanding how to write it, here is an example of how the parameters change during one specific call:
spiral(5, 90, 0, 3);
  forward(0);
  left(90);
  spiral(4,90,3,3);
    forward(3);
    left(90);
    spiral(3,90,6,3);
      forward(6);
      left(90);
      spiral(2,90,9,3);
        forward(9);
        left(90);
        spiral(1,90,12,3);
          forward(12);
          left(90);
          spiral(0,90,12,3);