digraph classes {
    graph [rankdir=RL];
    node [shape=rect, style=filled, fontname=Arial, fontsize=10];
    edge [];

    /* Mixin classes */
    node [color="#c69ee0", fontcolor="#000000"]

    /* Abstract classes */
    node [color="#9ec6e0", fontcolor="#000000"]

    GPIODevice;
    SmoothedInputDevice;

    /* Concrete classes */
    node [color="#2980b9", fontcolor="#ffffff"];

    Button->DigitalInputDevice;
    DigitalInputDevice->InputDevice;
    DistanceSensor->SmoothedInputDevice;
    InputDevice->GPIODevice;
    LightSensor->SmoothedInputDevice;
    LineSensor->SmoothedInputDevice;
    MotionSensor->SmoothedInputDevice;
    SmoothedInputDevice->InputDevice;
}
