i=0                                                    ;makes a variable
Gui, Add, Text, vP x0 y0, The value of i is %i%        ;the command v is to make a variable in the text so you can control it
Gui, Show                                            ;Show the gui
i++                                                    ;i+1
Sleep, 500                                            ;Wait a half second
GuiControl,, P, The value of i is %i%                Control the variable P and set it to the new value of i