WaveDrom draws your Timing Diagram or Waveform from simple textual description.
It comes with description language, rendering engine and the editor.
WaveDrom editor works in the browser or can be installed on your system.
Rendering engine can be embeded into any webpage.

Explanation of the possible states of a Linux process.

Free real-time operating system for embedded systems. Can run with 1.5 kB of RAM and 5 kB of ROM. Native ports are available for OS X and Linux.

Helical antenna for UHF (437 MHz).

spigot is a calculating program. It supports the usual arithmetic operations, square and cube roots, trigonometric and exponential functions, and a few other special functions such as erf.

spigot differs from the average calculating program in that it is an exact real calculator. This means that it does not suffer from rounding errors; in principle, it can keep generating more and more digits of the number you asked for until it runs out of memory.

In particular, if you ask for a complex expression such as sin(sqrt(pi)), then most calculating systems would compute first pi, then sqrt(pi) and finally sin(sqrt(pi)), accumulating a rounding error at each step, so that the final result had a build-up of error and you would have to do some additional error analysis to decide how much of the output you could trust.

spigot, on the other hand, does not output any digit until it is sure that digit is correct, so if you ask for (say) 100 digits of sin(sqrt(pi)) then you can be sure they are the right 100 digits.

How to choose and configure keyboards for efficient typing. Found Wed Dec 21 18:38:57 2016, rediscovered Tue Aug 28 01:08:05 2018.
The blog has other interesting articles, e.g. https://stevelosh.com/blog/2018/08/a-road-to-common-lisp/, https://stevelosh.com/blog/2013/09/teach-dont-tell/

Apart from the Scheme compiler Chicken
 http://www.call-cc.org/
two other Scheme and one Forth system, there is
 MA, a minimalistic variant of the Acme editor, written in Tcl/Tk.

sshguard protects hosts from brute-force attacks against SSH and other services. It aggregates system logs and blocks repeat offenders using one of several firewall backends, including iptables, ipfw, and pf.

Lots of interesting circuits, on-line calculators, ...