Many people are building small playgrounds for their children. Step-1 presents symple 2,4 m high structure which can be used as a climbing wall, base to support a slide, ...

Step-2 - added pyramid on the top changes the structure in a shape of tent  and the "tent" gets the door in step-3. Few kids have enough space to play inside the structure.

When the kid grows, the climbing wall must grow too. For step-4 additional supporting structure, 3 rectangular elements and some other small elements are needed. The height - 3,6 meters. A roof can be attached in step-5 for protection and top-out.

If the interest grows, the step-6 is possible. For more complex shape step-7 can be performed.

This story can go on and on. If somebody in the neighbouhood is using the same system - they can be joined. If the interest falls - elements can be sold. 

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