Example making text look glitchy

import random
import pygame

class RandomSwitchTimer:
    def __init__(self, ticks, on_intervals, off_intervals):
        self.next_ticks = ticks + random.choice(on_intervals)
        self.on_intervals = on_intervals
        self.off_intervals = off_intervals
        self.switch = True

    def tick(self, ticks):
        if ticks > self.next_ticks:
            if self.switch:
                self.next_ticks += random.choice(self.on_intervals)
                self.switch = False
            else:
                self.next_ticks += random.choice(self.off_intervals)
                self.switch = True

            return True
        return False

class GlitchEffect:
    def __init__(self, sprite):
        self.sprite = sprite
        ticks = pygame.time.get_ticks()
        self.blink_timer = RandomSwitchTimer(ticks,
                            (600, 999, 1222, 1556),
                            (40, 48, 54))
        self.jump_timer = RandomSwitchTimer(ticks,
                            (140, 401, 703),
                            (30, 54, 101))
        self.show = True
        self.rect = sprite.rect.copy()

    def draw(self, surface):
        if self.show:
            surface.blit(self.sprite.image, self.sprite.rect)

    def update(self, ticks):
        if self.blink_timer.tick(ticks):
            self.show = not self.blink_timer.switch

        if self.jump_timer.tick(ticks):
            if self.jump_timer.switch:
                self.sprite.rect = self.rect.copy()
            else:
                self.sprite.rect.y -= random.choice((-7, -4, 3))

def sprite_text(font, text, position, color, anchor):
    sprite = pygame.sprite.Sprite()
    sprite.image = font.render(text, 1, color)
    sprite.rect = sprite.image.get_rect()
    setattr(sprite.rect, anchor, position)
    return sprite

class SimpleWindow:
    def __init__(self, caption, width, height, flags=0):
        # Basic pygame setup
        pygame.display.set_caption(caption)
        self.surface = pygame.display.set_mode((width, height), flags)
        self.rect = self.surface.get_rect()
        self.clock = pygame.time.Clock()
        self.exit_window = False
        self.delta = 0
        self.fps = 60

        self.scene()

    def scene(self):
        font = pygame.font.Font(None, 36)
        text = sprite_text(font, "1999", self.rect.center, "red", "center")
        text.image.set_alpha(100)
        self.effect = GlitchEffect(text)

    def on_draw(self):
        self.surface.fill("black");
        self.effect.draw(self.surface)

        # update
        ticks = pygame.time.get_ticks()
        self.effect.update(ticks)

    def run(self):
        while not self.exit_window:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    self.exit_window = True

            self.on_draw()
            pygame.display.flip()
            self.delta = self.clock.tick(self.fps)

if __name__ == "__main__":
    pygame.init()
    window = SimpleWindow("Text Effects", 800, 600)
    window.run()
    pygame.quit()