Linear combination of vectors in space

Topic:
Vectors
Place the mouse cursor on a red point and start clicking. Four horizontal arrows or two vertical arrows are being displayed around the point while you are clicking. This indicates that the point is in the horizontal or int the vertical "move" mode. Clicking the point switches between the horizontal and the vertical mode. Press and hold the left mouse button and then move the mouse. Depending on the current mode, the point will move horizontally or vertically.