Electrically controlled terahertz (THz) beamforming antennas are essential for various applications such as wireless communications, security checks, and radar to improve coverage and information capacity. The emerging programmable metasurface provides a flexible, cost-effective platform for THz beam steering. However, scaling such arrays to achieve high-gain beam steering faces several technical challenges. Here, we propose a pixelated liquid crystal THz metasurface with a crossbar structure, thereby increasing the array scale to more than 3000. The coding pattern on the programmable device is generated by the modulo-addition of the coding sequences on the top and bottom layers. We experimentally demonstrate the programmable liquid crystal metasurface capable of active beam deflection in the upper half-space. This scale-up of programmable devices opens exciting opportunities in pencil beamforming, high-speed information processing, and optical computing.