A start to tiling the screen with triangles

At the moment, I'm trying to get started trying to tile the python turtle graphics screen with equilateral triangles of random colors. I've made a function which is successfully able to make a triangle starting at say coordinates v_1 = (x, y). Once it's made the triangle, I want the turtle to head to one of the other triangle vertices that are not equal to v_1 and start a new triangle there. I'd like to do all of this in a while loop. However, when I run my code, it seems that the turtle always goes back to the initial position of the first equilateral triangle and makes a new one on top of it. I'm not sure what I'm doing wrong. Here's my code:

from turtle import Turtle, colormode, done
from random import randint
colormode(255)


def make_left_triangle(bob: Turtle, x: float, y: float) -> None:
    """Makes an equilaterial triangle at coordinates (x, y) with the turtle bob moving left."""
    r: int = randint(0, 255)
    g: int = randint(0, 255)
    b: int = randint(0, 255)
    rand_n: int = randint(1, 2)
    i: int = 0
    bob.penup()
    bob.goto(x, y)
    bob.pendown()
    bob.fillcolor(r, g, b)
    bob.begin_fill()
    while i < 3:
        bob.forward(200)
        bob.left(120)
        i += 1
    bob.end_fill()
    while rand_n < 3:
        bob.forward(200)
        bob.left(120)
        rand_n += 1


def main() -> None:
    bob: Turtle = Turtle()
    i: int = 0
    rand_n: int = randint(25, 50)
    x_coord: float = 0
    y_coord: float = 0
    while i < rand_n:
        make_left_triangle(bob, x_coord, y_coord)
        x_coord = bob.pos()[0]
        y_coord = bob.pos()[1]
        i += 1
    done()


if __name__ == "__main__":
    main()

Any help on what's going wrong would be greatly appreciated! Thanks