is standard deviation is 5 pixels in size. The <code>expand = 3</code> argument tells ggfx to “expand” each point by 3 pixels before drawing the glow. This can be handy for very small objects that would otherwise be difficult to see even with the added glow.</p>
<p>When written like this – with each layer stored as a named variable – ggfx code is very easy to read. I’ve quickly found myself adopting this code style any time I want to do pixel filtering. Constructing the plot piecewise and storing 