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

    /* Abstract classes */
    node [color="#9ec6e0", fontcolor="#000000"]
    Device;
    SPIDevice;
    AnalogInputDevice;
    MCP3xxx;
    MCP33xx;

    /* Concrete classes */
    node [color="#2980b9", fontcolor="#ffffff"];
    SPIDevice->Device;
    AnalogInputDevice->SPIDevice;
    MCP3xxx->AnalogInputDevice;
    MCP33xx->MCP3xxx;
    MCP3004->MCP3xxx;
    MCP3008->MCP3xxx;
    MCP3204->MCP3xxx;
    MCP3208->MCP3xxx;
    MCP3301->MCP33xx;
    MCP3302->MCP33xx;
    MCP3304->MCP33xx;
}
