How to make a mesh within rectangle using drawing functions of the OpenCV?

This is my full code.

import cv2
import numpy as np


cap = cv2.VideoCapture(0)

width = cap.get(3)  # float
height = cap.get(4)  # float
print (width, height)

while (1):
    _, img = cap.read()

    if _ is True:
        hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
    else:
        continue
    # blue color

    blue_lower = np.array([86,0,90], np.uint8)
    blue_upper = np.array([163, 64, 145], np.uint8)
    blue = cv2.inRange(hsv, blue_lower, blue_upper)
    kernal = np.ones((9, 9), "uint8")
    blue = cv2.dilate(blue, kernal)
    res_blue = cv2.bitwise_and(img, img, mask=blue)

            # Tracking blue
    (_, contours, hierarchy) = cv2.findContours(blue, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    for pic, contour in enumerate(contours):
        area = cv2.contourArea(contour)
        if (area > 2000):
            print (area)
            x, y, w, h = cv2.boundingRect(contour)
            img = cv2.rectangle(img, (x, y), (x + w, y + h), (255, 0, 0), 2)
            cv2.putText(img, "Blue Colour", (x, y), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (255, 0, 0))

            # cv2.putText(img, "Blue Colour", (x, y), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (255, 0, 0))
    cv2.imshow("Color Tracking", img)
    if cv2.waitKey(10) & 0xFF == ord('q'):
        cap.release()
        cv2.destroyAllWindows()
        break

I would like to mesh all rectangles as these pictures. you can see the mesh of the contour next to them. In my case, I would like to mesh rectangles themselves.

This picture is taken from this video

please explain what “mesh” means here
(did you mean “hull” ?)

The sloped lines within the contour.

related:

yes. it is the same question.