Snake Concept Pygame & PyDroid

import pygame_sdl2
pygame_sdl2.import_as_pygame()
import pygame
import sys

# define some colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)

pygame.init()
DS = pygame.display.set_mode((640, 480))
CLOCK = pygame.time.Clock()

FPS = 30

W = DS.get_width()
H = DS.get_height()
HW, HH = int(W / 2), int(H / 2)

segmentSize = 20
hx = 0
hy = -segmentSize
sx = HW
sy = HH

tail = [[sx, sy + index * segmentSize] for index in range(10)]

for segment in tail:
    pygame.draw.rect(DS, WHITE, (segment[0], segment[1], segmentSize, segmentSize), 0)

pressed = False

while True:
    e = pygame.event.get()

    pygame.draw.rect(DS, WHITE, (sx, sy, segmentSize, segmentSize), 0)

    sx += hx
    sy += hy

    tail.insert(0, [sx, sy])

    pygame.draw.rect(DS, BLACK, tail.pop() + [segmentSize, segmentSize], 0)

    mb = pygame.mouse.get_pressed()[0]

    if mb and not pressed:
        mx1, my1 = pygame.mouse.get_pos()
        pressed = True
    elif not mb and pressed:
        pressed = False
        mx2, my2 = pygame.mouse.get_pos()
        dx = mx2 - mx1
        dy = my2 - my1
        if dx > 200 and not hx:
            hx = segmentSize
            hy = 0
        elif dx < -200 and not hx:
            hx = -segmentSize
            hy = 0
        elif dy > 200 and not hy:
            hx = 0
            hy = segmentSize
        elif dy < -200 and not hy:
            hx = 0
            hy = -segmentSize
    if pressed:
        pygame.draw.line(DS, WHITE, (mx1, my1), pygame.mouse.get_pos(), 1)

    pygame.display.update()
    #DS.fill(BLACK)
    CLOCK.tick(FPS)