Digital technologies/Laser cutting/Vector graphics- Intermediate/Extensions
Extensions[1] built into Inkscape can make designing easier and add more functionality to the software. There are a diverse number of extensions available in Inkscape for various purposes. For example, if you want to create something round or curved, you can use the Living Hinge extension. An example is shown below:

They can be accessed easily from the Extension toolbar, shown in the picture below, while other extensions created by the Inkscape community can easily be downloaded from Inkscape extension gallery online, here.

Installing an extension
To install an extension, follow the following steps:
1.Download and unpack the archive file from the website
2.Determine the location where to copy these files:
In Inkscape: Edit->Preferences-> System: User Extensions

3.Locate this path on your computer and copy the two files from the download (.inx and .py files)
4.Restart Inkscape, and you should now be able to access it from the Extensions on the toolbar
Extensions in Inkscape
Once downloaded, you can find the extensions in Inkscape, available to use in different projects. A commonly used extension is the living hinge.
Living hinges
A living hinge is a flexible part of an object that allows movement between two segments. It can be attained by creating a series of thin lines that are cut, hence enabling the object to bend without breaking. Instead of creating several lines to be vectored, which can be time-consuming, you can use the available Inkscape extension by going to Extension->Render->Living hinge.
Other extensions
More extensions are available for download here.They range from laser-cut boxes, jigsaws, shapes, gears, calendars and much more.

- ↑ https://www.tutkit.com/en/text-tutorials/6478-discover-the-advanced-features-in-inkscape