Drawing line by spawning blocks in runtime

My team is trying to make a puzzle game where player draw line on screen as a wall/obstruct to change some ball’s moving direction.

here’s my solution so far:

void Update () 
	{
		//if(canDraw == true)
		//{
			if(Input.GetKeyDown(KeyCode.Mouse0))
			{
				StartCoroutine("DrawingBlocks");
			}
			if(Input.GetKeyUp (KeyCode.Mouse0))
			{
				StopCoroutine("DrawingBlocks");
			}
		//}
	
	}
	void DrawSwitchOff()
	{
		canDraw = false;
	}
	void DrawSwitchOn()
	{
		canDraw = true;
	}
	IEnumerator DrawingBlocks()
	{
		mousePos1 = Camera.main.ScreenToWorldPoint(Input.mousePosition);
		while(true)
		{
			
			yield return new WaitForSeconds(0.01f);//block spawning interval
			mousePos2 = Camera.main.ScreenToWorldPoint(Input.mousePosition);
			blockDrawPos = new Vector3 ((mousePos1.x + mousePos2.x) / 2, (mousePos1.y + mousePos2.y) / 2, 0);
			blockRotation = new Vector3(mousePos2.x - mousePos1.x, mousePos2.y - mousePos1.y, 0);
			// don't draw if mouse didn't move
			if(mousePos1 != mousePos2)
			{
				GameObject clone;
				if(canDraw == true)
				{
					//spawn a block in middle of 2 mouse position
					clone = Instantiate(Block, blockDrawPos, Quaternion.LookRotation(blockRotation)) as GameObject;
					//send message to ink monitor
					inkUsed.SendMessage("inkUsed",1);
					//change spawned block's scale to fill the distance between 2 mouse position
				clone.gameObject.transform.localScale += new Vector3 (0, 0, Vector3.Distance(mousePos1, mousePos2));
				}
			}
			mousePos1 = mousePos2;
		}
		
	}

It detects mouse position (before and after) every short amount of time and spawn a block(with a box collider) in between and change its scale to fill the gap, It works fine but the line seems too jagged sometime if the mouse is moving at a very low speed.
Also because of the jagged line the collider is also jagged so the balls is bouncing weird.
My question is: Is there a better way to achieve this to make the line looks smooth? And make the collider boxes connect smoothly so the balls wouldn’t bounce to unwanted direction. Thank you.

Why not rotate the boxes to match the direction of the line? Or just make one box and stretch it in the direction of the line?