The Ding side contains 8 tone fields which together form the "tone circle" (scale or mode). This circle surrounds a central dome, called the Ding, which sounds like a Gong. On the Gu side (underneath), there is a hand size hole called the Gu for sound resonance. The Gu can also be played like an udu, or used to modulate the sound of the DING. The instrument is generally held in the player's lap and played with the hands, although it can also be played with soft mallets. By changing the position of his/her knees, the player can change the deep note and vary the timbre of the instrument while playing. The Caribbean steelpan is probably the most important new acoustical instrument to develop in the 20th century. Since its invention in Trinidad some 50 years ago, improvements in the technology and design have resulted from research in Europe and the United States in addition to its home country of Trinidad and Tobago. It has also inspired the development of new steel instruments, such as the PANG family of instruments and the hand-played HANG