Can you tie a knot in four dimensions? A mathematician explains

Four-dimensional space contains an additional independent direction beyond our familiar three dimensions. While humans cannot visualize four dimensions, mathematicians use analogies to understand them, such as drawing four-dimensional cubes by connecting two three-dimensional cubes corner to corner. Knots would be impossible in four-dimensional space because ropes could slip through each other by moving in the fourth direction, though two-dimensional surfaces like balloons could still be knotted.