Use the [icon]/images/ggb/toolbar/mode_point.png[/icon] and [icon]/images/ggb/toolbar/mode_planethreepoint.png[/icon] tools to add a second plane to the applet below. [br]Then use the the [icon]/images/ggb/toolbar/mode_intersect.png[/icon] tool to show the intersection of these two planes.[br][br]Now use the [icon]/images/ggb/toolbar/mode_move.png[/icon] tool (click and hold) to rotate the planes and see that the intersection is ALWAYS a plane.