Instructable by donedirtcheap. This is absolutely brilliant and I can't wait until my son is old enough to appreciate it. Or eat solid food.

(Manual) Calibration points for my Prusa I3:

G1 F3000
G1 X0 Y30
G1 X0 Y200
G1 X150 Y200
G1 X150 Y30

More objects to make:

Some notes on auto bed levelling:

Luke recommended Working Effectively with Legacy Code. A couple of slide decks from CalPoly and Object Mentor cover some of the high points.

Essentially, Feathers defines legacy software as software without sufficient test coverage. Which is a sufficient insight in and of itself.

I love the idea of tests as a software vice. When machining metal, a vice holds the work steady. You don't use a vice to modify anything. It doesn't perform any operation aside from keeping your work oriented and positioned so you can do something to it. Tests are there to keep your software from squirming.

Anxiety occurs when people try to do today’s jobs with yesterday’s tools.

-- Marshall McLuhan

(Via Paper Bits and Stowe Boyd)