ViewControllerAndMotionVariables.swift

//MARK: Motion (Accelerometer and Gyroscope)
    
/// motionManager will be what we'll use to get device motion
var motionManager = CMMotionManager()

/// this will be the "device’s true orientation in space" (Source: https://nshipster.com/cmdevicemotion/)
var initialAttitude: CMAttitude?

/// we'll later read these values to update the highlight's position
var motionX = Double(0) /// aka Roll
var motionY = Double(0) /// aka Pitch