Cat and Mouse lab base

Cat.cs

using UnityEngine;
using System.Collections;

public class Cat : MonoBehaviour {

	// 	declare a public variable, of type Transform, called "mouse"
	public Transform mouse;

	bool shouldIPlayASound = false;

	void FixedUpdate () {
		//	declare a var of type Vector3, called "directionToMouse", set to a vector that goes from [current position] to [mouse's current position]
		Vector3 directionToMouse = mouse.position - transform.position;

		// if the angle between [current forward direction] vs. [directionToMouse] is less than 90 degrees, then...
		if ( Vector3.Angle ( transform.forward, directionToMouse ) < 90f ) {
			//	declare a var of type Ray, called "catRay" that starts from [current position] and goes toward [mouse's current position]
			Ray catRay = new Ray( transform.position, directionToMouse );
			//	declare a var of type RaycastHit, called "catRayHitInfo"
			RaycastHit catRayHitInfo = new RaycastHit();
			//	if raycast with catRay and catRayHitInfo for 100 units is TRUE...
			if ( Physics.Raycast ( catRay, out catRayHitInfo, 100f ) ) {
				//	if catRayHitInfo.collider.tag is exactly equal to the word "Mouse"...
				if ( catRayHitInfo.collider.tag == "Mouse" ) {
					// the cat can see the mouse, play a sound
					if ( GetComponent<AudioSource>().isPlaying == false && shouldIPlayASound == false ) {
						GetComponent<AudioSource>().Play ();
						shouldIPlayASound = true;
					}

					Debug.DrawRay ( catRay.origin, catRay.direction * 100f, Color.yellow );
					// if catRayHitInfo.distance is less than or equal to 5...
					if ( catRayHitInfo.distance <= 5f ) {
						//	then destroy the mouse object (we caught the mouse!)
						Destroy ( mouse.gameObject );
					} else {
						//	move toward the mouse!
						GetComponent<Rigidbody>().AddForce (directionToMouse.normalized * 1000f);
					}
				} else {
					shouldIPlayASound = false; // reset sound variable
				}
			}
		}
	}
}

Mouse.cs

using UnityEngine;
using System.Collections;

public class Mouse : MonoBehaviour {

	//declare a public variable, of type Transform, called "cat"
	public Transform cat;

	void FixedUpdate () {
		// declare a var of type Vector3, called "directionToCat", set to a vector that goes from [current position] to [cat's current position]
		Vector3 directionToCat = cat.position - transform.position;

		// if the angle between [current forward direction] vs. [directionToCat] is less than 180 degrees, then...
		if ( Vector3.Angle ( transform.forward, directionToCat ) < 180f ) {
			// declare a var of type Ray, called "mouseRay" that starts from [current position] and goes toward [cat's current position]
			Ray mouseRay = new Ray( transform.position, directionToCat );
			// declare a var of type RaycastHit, called "mouseRayHitInfo"
			RaycastHit mouseRayHitInfo = new RaycastHit();
			// if raycast with mouseRay and mouseRayHitInfo for 100 units is TRUE, then...
			if ( Physics.Raycast ( mouseRay, out mouseRayHitInfo, 100f ) ) {
				// if mouseRayHitInfo.collider.tag is exactly equal to the word "Cat"...
				if ( mouseRayHitInfo.collider.tag == "Cat" ) {
					Debug.DrawRay ( mouseRay.origin, mouseRay.direction * 100f, Color.cyan );
					// run away from the cat!
					GetComponent<Rigidbody>().AddForce ( (-directionToCat.normalized-transform.forward) * 1000f);
				}
			}
		}
	}
}

Movement.cs

using UnityEngine;
using System.Collections;

public class Movement : MonoBehaviour {

	// Update is called once per frame
	void FixedUpdate () {
		// Add a physics force going forward (to always move forward)
		GetComponent<Rigidbody>().velocity = transform.forward * 10f + Physics.gravity;

		// declare a var of type Ray, called "moveRay" that starts from [current position] and goes [current forward direction]
		Ray ray = new Ray( transform.position, transform.forward );

		// if Raycast with moveRay for 3 unit is TRUE...
		if ( Physics.SphereCast ( ray, 0.5f, 3f ) ) {
			// then randomly turn 90 degrees left or right (around Y axis)
			transform.Rotate (0f, Random.value > 0.5 ? -90f : 90f, 0f );
		}
	}

}