Rotate counterclockwise

define Rotate counterclockwise about x: (x :: custom-arg) y: (y :: custom-arg) by (angle :: custom-arg) degrees
set [dx v] to ((x position) - (x :: custom-arg))
set [dy v] to ((y position) - (y :: custom-arg))
change x by ((((dx) * ([cos v] of (angle :: custom-arg))) - ((dy) * ([sin v] of (angle :: custom-arg)))) - (dx))
change y by ((((dx) * ([sin v] of (angle :: custom-arg))) + ((dy) * ([cos v] of (angle :: custom-arg)))) - (dy))