THE ROBOT IS building a tesseract. He motions at a glowing cube floating before him, and an identical cube emerges. He drags it to the left, but the two cubes stay connected, strung together by glowing lines radiating from their corners. The robot lowers its hands, and the cubes coalesce into a single shape—with 24 square faces, 16 vertices, and eight connected cubes existing in four dimensions. A tesseract.