An image kernel is a matrix that's used to apply effects such as blurring, sharpening, outlining or embossing. Image kernels are also used in machine learning for feature extraction, which is a technique to determine the most important portions of an image. Here's how they work.
This site puts one year's State of the Union in context with any other. Select a word or two, and a frequency graph of those words is displayed according to their use by other presidents. This is built on the Bookworm project, which is available on GitHub and allows for easy analysis of text repositories.
Plotting data in Python is a good news/bad news story. The good news is that there are a lot of options. And the bad news is that there are a lot of options. Here's an overview of what those options are and when to use them.