Creating A Rainbow Design using turtle

Rainbow Design.py

import turtle as t

t.speed(5)
t.bgcolor('black')

r, g, b = 255, 0, 0

for i in range(255 * 2):
    t.colormode(255)
    if i < 255 // 3:
        g += 3
    elif i < 255 * 2 // 3:
        r -= 3
    elif i < 255:
        b += 3
    elif i < 255 * 4 // 3:
        g -= 3
    elif i < 255 * 5 // 3:
        r += 3
    else:
        b -= 3

    t.forward(50 + i)
    t.right(91)

    t.pencolor(r, g, b)

t.hideturtle()
t.done()