---
title: Modeling Variability 4
categories: demo
toc: false
...

Composing subsystems back into the Car.

```clafer
abstract Car
    ABS ?
    xor Transmission
        Automatic
        Manual
    `FCA ?
    `CC ?
```

The Forward Collision Alert (FCA) subsystem.

```clafer
abstract FCA
        xor Sensor
            Radar
            Lidar
        xor Alert
            Haptic
            Audible
```

The Cruise Control (CC) subsystem.

```clafer
abstract CC
        switch
            backlight ?
        ACC ?
```

```{.clafer .graph}
```

[Modeling Variability 5]()