Polar coordinate

Hi all,

I'd like to make a polar coordinate system for a loading screen, but i don't have understand the math behind it ( i'm not good in math but i like programming )

This is the basic script:

#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>

$Form1 = GUICreate("Form1", 450, 450, -1, -1)
$Label1 = GUICtrlCreateLabel("a", 225, 15, 20, 50)
GUICtrlSetBkColor(-1, "000000")
For $x = 1 To 12
    ;how to do?
Next
GUISetState(@SW_SHOW)


While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit

    EndSwitch
WEnd

I'd like to di it with simply colored label and GuiCtrlSetPos.

A little help, thanks