2D pixel art tileset sprite sheet, strictly top-down overhead view, grid layout with clear spacing, includes: light gray floor tile, white inner floor tile, dark gray wall tile, thick border wall tile, corner wall pieces, door opening tile, wall vent tile, each tile 32x32 pixels, two passage way in the left and right corner, transparent background, clean indoor sci-fi lab style, no perspective or isometric angle, consistent top-down pixel art style