updateHighlightsAttitude.swift

func updateHighlightOrientations(attitude: CMAttitude) {
    /// initialAttitude is an optional that points to the reference frame that the device started at
    /// we set this when the device lays out it's subviews on the first launch
    if let initAttitude = initialAttitude {

        /// We can now translate the current attitude to the reference frame
        attitude.multiply(byInverseOf: initAttitude)

        /// Roll is the movement of the phone left and right, Pitch is forwards and backwards
        let rollValue = attitude.roll.radiansToDegrees
        let pitchValue = attitude.pitch.radiansToDegrees

        /// This is a magic number, but for simplicity, we won't do any advanced trigonometry -- also, 3 works pretty well
        let conversion = Double(3)

        /// Here, we figure out how much the values changed by comparing against the previous values (motionX and motionY)
        let differenceInX = (rollValue - motionX) * conversion
        let differenceInY = (pitchValue - motionY) * conversion

        /// Now we adjust every highlight's potision
        for highlight in previousHighlightComponents {
            highlight.frame.origin.x += CGFloat(differenceInX)
            highlight.frame.origin.y += CGFloat(differenceInY)
        }

        /// finally, we put the new attitude values into motionX and motionY so we can compare against them in 0.03 seconds (the next time this function is called)
        motionX = rollValue
        motionY = pitchValue
    }
}