In my previous professional life, I processed a lot of credit card numbers.
When reading credit card numbers from an unknown source, it helps to have a fast
way of checking basic validity — to filter out bogus input. Such a method
exists: the Luhn algorithm. I developed a very fast implementation of the
algorithm a few years ago, and I keep seeing it pop up other places.
Polylactic Acid is a compostable
plastic that can be made from renewable resources — usually plants. Compared
to ABS plastic, it’s much harder, warps much less, and can be crystal clear.
When I first got my hands on some PLA filament in 2009, it had the potential to
be my new favorite plastic…but getting it working took time.