如何在glowscript/VPython中模拟多个弹丸轨迹？

from vpython import *

class Projectile:
    def __init__(self, position, velocity, radius, color):
        self.ball = sphere(pos=position, radius=radius, color=color)
        self.velocity = velocity

scene = canvas(title='Multiple Projectile Trajectories', width=800, height=600)
scene.camera.pos = vector(0, 0, 50)
scene.camera.axis = vector(0, 0, -50)

projectiles = [
    Projectile(vector(-10, 0, 0), vector(5, 0, 0), 0.5, color.red),
    Projectile(vector(10, 0, 0), vector(-5, 0, 0), 0.5, color.blue)
]

dt = 0.01
total_time = 10

for t in arange(0, total_time, dt):
    rate(100)
    for projectile in projectiles:
        projectile.ball.pos += projectile.velocity * dt
        projectile.velocity.y += -9.8 * dt

ground = box(pos=vector(0, -5, 0), size=vector(30, 0.1, 10), color=color.green)