Conic Sections

Move the red dot by "Angle of Plane" to change how the plane tilts.
Move the red dot on the plane to move the plane up or down.
Drag the "Adjust Cone" dot to adjust the width of the cone.
You can change the 3d-view by dragging the corners of the cube, and move the purple graph around by dragging in the white area of the window (also panning and zooming works).