Seperated "Square.cs" and "PathRenderer.cs".

Assets/Scripts/PathRenderer.cs

+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+using System.Linq;
+
+public class PathRenderer : MonoBehaviour
+{
+    [SerializeField]
+    Square square;
+
+    LineRenderer _pathRenderer;
+    float _zPosition => square.transform.position.z;
+
+    // Start is called before the first frame update
+    void Start()
+    {
+        _pathRenderer = GetComponent<LineRenderer>();
+        _ResetPaths();
+    }
+
+    // Update is called once per frame
+    void Update()
+    {
+        if (Input.GetMouseButtonDown(1))
+        {
+            RaycastHit hit;
+            var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
+
+            if (Physics.Raycast(ray, out hit))
+            {
+                if (Input.GetKey(KeyCode.LeftShift))
+                {
+                    Debug.Log("asdf");
+                    _DrawMorePath(hit.point);
+                }
+                else
+                {
+                    _DrawOnePath(hit.point);
+                }
+            }
+        }
+    }
+
+    private void _DrawOnePath(Vector3 point)
+    {
+        _ResetPaths();
+        point.z = _zPosition;
+        square.pathList[0] = transform.position;
+        square.pathList[1] = point;
+        _pathRenderer.SetPositions(square.pathList.ToArray());
+    }
+
+    private void _ResetPaths()
+    {
+        _pathRenderer.positionCount = 2;
+        square.pathList.Clear();
+        square.pathList.Add(transform.position);
+        square.pathList.Add(new Vector3(0, 0, _zPosition));
+        _pathRenderer.SetPositions(square.pathList.ToArray());
+    }
+
+    private void _DrawMorePath(Vector3 point)
+    {
+        point.z = _zPosition;
+        square.pathList.Add(point);
+        _pathRenderer.positionCount = square.pathList.Count();
+        _pathRenderer.SetPositions(square.pathList.ToArray());
+    }
+}

Assets/Scripts/PathRenderer.cs.meta

+fileFormatVersion: 2
+guid: 8f30fcfb85a9c704291c91129b0b8f0c
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/Square.cs

@@ -6,61 +6,6 @@ using System.Linq;
 
 public class Square : FlatLandObject
 {
-
-    public LineRenderer pathRenderer; // About drawing paths.
     public List<Vector3> pathList = new List<Vector3>();
     private float _zPosition => transform.position.z;
-
-    private void Awake()
-    {
-        _ResetPaths();
-    }
-
-    private void Update()
-    {
-        if (Input.GetMouseButtonDown(1))
-        {
-            RaycastHit hit;
-            var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
-
-            if (Physics.Raycast(ray, out hit))
-            {
-                if (Input.GetKey(KeyCode.LeftShift))
-                {
-                    Debug.Log("asdf");
-                    _DrawMorePath(hit.point);
-                }
-                else
-                {
-                    _DrawOnePath(hit.point);
-                }
-            }
-        }
-    }
-
-    private void _DrawOnePath(Vector3 point)
-    {
-        _ResetPaths();
-        point.z = _zPosition;
-        pathList[0] = transform.position;
-        pathList[1] = point;
-        pathRenderer.SetPositions(pathList.ToArray());
-    }
-
-    private void _ResetPaths()
-    {
-        pathRenderer.positionCount = 2;
-        pathList.Clear();
-        pathList.Add(transform.position);
-        pathList.Add(new Vector3(0, 0, _zPosition));
-        pathRenderer.SetPositions(pathList.ToArray());
-    }
-
-    private void _DrawMorePath(Vector3 point)
-    {
-        point.z = _zPosition;
-        pathList.Add(point);
-        pathRenderer.positionCount = pathList.Count();
-        pathRenderer.SetPositions(pathList.ToArray());
-    }
 }