Pngquant is a free, open source and cross-platform command-line lossy PNG compressor. It is based on a portable libimagequant library and is written in C99. It reduces the file size significantly by converting the PNG image to more efficient 8-bit PNG format and preserves full alpha transparency. As you may already know, 8-bit PNG files are often 60-80% smaller than 24/32-bit PNG files. The images compressed using Pngquant are fully-compatible with all web browsers and operating systems. Pngquant can compress one or multiple images at once.

A simulated Enigma machine, where the different parts of the machine are beautifully represented with graphics.

The notebook simulates an Enigma Machine and visualizes how it works. The Enigma Machine is an especially neat thing to visualize because it was electromechanical. As you used it, it moved. Instead of circuit traces, it had beautiful real wires connecting its pieces.

Image source: Wikipedia.