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Design pattern:
	Bridge

Description:
	"Decouple an abstraction from its implementation so that the two
	can vary independently."

This pattern can be used with both classes and prototypes.

In this sample implementation, we use classes for representing the
abstraction part of the pattern and prototypes for the implementation
part. As discussed in the pattern description, the instances in the
abstraction hierarchy use object composition to refer to and delegate
operations to the implementation hierarchy objects.

Print Logtalk, Prolog backend, and kernel versions (if running as a notebook):

```logtalk
%versions
```

Start by loading the design pattern sample implementation:

```logtalk
logtalk_load(design_patterns('structural/bridge/loader')).
```

Draw the static instance of circle:

```logtalk
a_circle::draw.
```

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API2: circle at 1.7:11.3 with radius 2.1

true.
-->

Create a couple of dynamic circles, resize them by 25%, and draw them:

```logtalk
circle::new(Circle1, [drawing_api(drawing_api_1), x(1.0), y(2.0), radius(3.0)]),
Circle1::(resize(25), draw).
```

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API1: circle at 1.0:2.0 with radius 3.75

Circle1 = o1.
-->

```logtalk
circle::new(Circle2, [drawing_api(drawing_api_2), x(5.0), y(7.0), radius(11.0)]),
Circle2::(resize(25), draw).
```

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Circle2 = o2.
-->
