This python code makes a 7 x 6 grid show up for Connect 4.

Connect 4, Grid Shows Up

from pyglet import app
from pyglet import clock
from pyglet.window import Window
from pyglet.window import mouse
from pyglet.window import key
from pyglet import graphics
from pyglet import gl
from pyglet import text
from math import sin, cos, pi

cols = 7 # don't change this
rows = 6 # don't change this
col_width = row_height = 140  #change if you like
grid_color = (255, 0, 255, 0)  #change color if you like

win_width = cols * col_width
win_height = rows * row_height

window = Window(win_width, win_height)

@window.event
def on_draw():
    window.clear()
    draw_grid()

def draw_grid():
    for i in range(cols):
        draw_line(i*row_height, 0, i*row_height, win_height, color = grid_color)
    for i in range(rows):
        draw_line(0, i*col_width, win_width, i*col_width, color = grid_color)
        
def draw_line(x1, y1, x2, y2, color = (255, 255, 255, 0)):
    graphics.draw(2, gl.GL_LINES, ('v2i', (x1, y1, x2, y2)), ('c4B', color * 2)   )
    
app.run()