@madskjeldgaard Morphological Operators

This operator looks at the pixels in its immediate neighborhood.
For example, if it sees that one of its neighboring pixels has a light color, it sets its pixel to that color.

So first draw the much too thin looking lines on the black background. Then in a subsequent pass apply the "dilate" operator to the image.

Often you have several passes dilate → dilate → erode → blur

source for OpenFrameworks
https://gitlab.com/metagrowing/ana/-/blob/master/visual_server/src/gl/GlMoOprFilter.cpp