BatmanCookieCutter

You can start with an image from the interweb or make one yourself in Inkscape. In this case I started with an existing image of the Batman logo

Choose Menu > File > Import in Inkscape. Make sure to "embed" the image and not "link" it.

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Embed an image in Inkscape

A path can be created from the image with Path > Trace bitmap. Tweak the settings untill you have the path you would like to use as a basis for your model. In this case the "brightness cutoff" was good, in other cases you might want to try the "edge detection" setting.

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Create path from an image

A new object has been created over the original image. The original can be removed. Give the path the dimensions you want the model to have.

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Resize object with fixed xy-ratio (the small lock button)

I wanted to use the elipse as a base and the logo as cutter. Therefore the path was divided into two paths by choosing Path > Break apart.

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Make distinct paths from the path with "Break apart"