I have made a fractal, and I noticed that some parts are disfigured. The reference shape in my code is symmetrical from left to right, but after like 2 levels of recursions the smaller shape is no longer symmetrical (relative to the rotation and size). I don’t know what could be causing this.

import pygame
from math import *

screen = pygame.display.set_mode((600,600))
clock = pygame.time.Clock()

def checkExit():
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()

def pointat2D(i,p):
    dx = p[0]-i[0]
    dy = p[1]-i[1]

    if dy == 0:
        if dx < 0:
            pd = -90
        else:
            pd = 90
    else:
        if dy < 0:
            pd = degrees(radians(180)+atan(dx/dy))
        else:
            pd = degrees(atan(dx/dy))
    return(pd)

def rotate(origin, point, angle):
    angle = radians(angle)
    
    ox,oy = origin
    px,py = point

    qx = ox+cos(angle)*(px-ox)-sin(angle)*(py-oy)
    qy = oy+sin(angle)*(px-ox)+cos(angle)*(py-oy)
    return [qx,qy]

size = 600

reference = [[0,0],[250,0],[300,-220],[350,0],[600,0]]

lines = [[100,300],[500,300]]

def recurse(amount=1):
    global lines
    for _ in range(amount):
        newLines = []

        for i in range(len(lines)-1):
            a = pointat2D(lines[i],lines[i+1])-90
            d = dist(lines[i],lines[i+1])
            
            t = []
            for p in reference:
                new = rotate([0,0],p,-a)
                new[0] *= d/size
                new[1] *= d/size
                t.append([new[0]+lines[i][0],new[1]+lines[i][1]])

            newLines.extend(t)
            
        lines = []
        #remove duplicates
        for i in newLines:
            if i not in lines:
                lines.append(i)

recurse(2)

zoom = 1
m = 0

focus = [300,153.33]

while True:
    checkExit()
    
    screen.fill((20,20,20))
    
    lines = [[100,300],[500,300]]
    
    mouse = list(pygame.mouse.get_pos())
    mouse[1] -= 300
    reference = [[0,0],[250,0],mouse,[350,0],[600,0]]
    
    recurse(3)
    # if zoom >= 1.2:
    #     zoom = 1.1
    # zoom += 0.001
    m = zoom**10
        
    display = list(map(lambda x: [(x[0]-focus[0])*m+focus[0],(x[1]-focus[1])*m+focus[1]],lines))
    
    pygame.draw.lines(screen,(255,255,255),False,display)
    
    pygame.display.update()
    clock.tick(60)

I apologize for posting mostly code, but there really isn’t any other way to show this problem.

I checked my code and it is perfectly symmetrical.

reference = [[0,0],[250,0],[300,-220],[350,0],[600,0]]

Maybe there is something wrong with my code? Or maybe this supposed to happen, idk.