Decades: 470s BC 460s BC 450s BC 440s BC 430s BC - 420s BC - 410s BC 400s BC 390s BC 380s BC 370s BC
429 BC 428 BC 427 BC 426 BC 425 BC 424 BC 423 BC 422 BC 421 BC 420 BC
... the gyro fall over.) The axis of the gyroscope in the Dynabee is fixed to the spinning mass and it rests in a little groove inside the wrist exerciser device, which ...