The distance between two parallel lines in space

1. Click to see points A and B on lines L1 and L2 respectively; 2. Click to see the vector AP; 3. Move the slider so that the vector AP is perpepndicular to L2; 4. Use "Rotate 3D Graphics View" to see from different perspectives; 5. For full 3D effect: Right click select Graphics - 3D Graphics - Projection - Glasses. Move the view to the right using your mouse and then put on your red-cyan 3D glasses and enjoy.