2 or 3 planes
1. On the top right, click on the "rotate" icon between the magnet and the cube to rotate the diagram (you can also change the speed of rotation). 2a. The first three sliders n_1x, n_1y and n_1z represent the components of n_1, the normal vector of the plane Π_1. 2b. Use the fourth slider to change the value of a_1 in the equation of the plane Π_1: r.n_1 = a_1. 2c. Click the checkbox to display the normal vector n_1. 3. You can choose to show the planes Π_2 and Π_3 as well.