translation.en: Allan McRobie is a bridge engineer from Cambridge who wrote to me, suggesting that a bridge simulator ought to wobble in the same way as the real bridge -- provided we hung it on pendulums of exactly the right length.
translation.zh: Allan McRobie是一位剑桥来的桥梁工程师。 他写信给我，建议建一座模拟桥 来模拟真实的桥的摆动—— 前提是我们把它悬挂在实际长度的摆挂上。