1. A handheld for use with an image of a virtual 3D space displayed on a stationary display to provide an immersive spatial human-machine interface, the handheld comprising: a housing dimensioned to be grasped and supported by the left and right hands of a user at opposite ends thereof, the housing being configured and dimensioned to move with the user's hands in free space to change position and orientation; a gyroscope disposed within the housing, the gyroscope sensing angular rate of the housing in three axes; an accelerometer disposed within the housing, the accelerometer sensing linear acceleration of the housing in three axes; a magnetometer disposed within the housing, the magnetometer sensing direction of the earth's magnetic north relative to the housing; a wireless transceiving arrangement disposed within the housing and coupled to the gyroscope, the accelerometer and the magnetometer, the wireless transceiving arrangement (a) wirelessly transmitting sensed angular rate, sensed linear acceleration and sensed magnetic north direction and (b) wirelessly receiving a video signal generated in response to the transmitted sensed angular rate, sensed linear acceleration and sensed magnetic north direction; and a display disposed on the housing, the display coupled to the wireless transceiving arrangement and configured to display moving images of a part of the virtual 3D space responsive to the received video signal to provide spatial correlation between the current attitude of the housing and images of part of the virtual world displayed by the display to thereby provide immersive 3D spatiality without requiring the user to be surrounded by displays.