---
title: Variant Derivation
toc: false
...

> Back to [Intro]()

Product line model:
==================

```clafer
abstract xor Bluetooth
    Bluetooth20 ?
    Bluetooth21 ?
    Bluetooth40 ?

abstract MobilePhone
    Connectivity
        `Bluetooth
        GSM
        LTE ?
            [LiBattery1400]
        WiFi ?
        USB ?
    xor Battery
        LiBattery1150 ?
        LiBattery1400 ?

abstract LowEndPhone : MobilePhone
    [no WiFi]

abstract HighEndPhone : MobilePhone
    [USB && WiFi]
    QuadCPU ?
```

Variant Configuration:
=====================

The customer requested `WiFi`, `LTE`, and `Bluetooth`. Carol proposed `Bluetooth21`.

```clafer
Phone1 : MobilePhone
   [ WiFi ] 
   [ LTE ]
   [ Bluetooth21 ]
```

Trying a high-end phone:

```clafer
Phone2 : HighEndPhone
   [ LTE ]
   [ Bluetooth21 ]
   [ QuadCPU ]
```