Unattended

Pl. VIII
Game

Pl. VIII · Game

Darkfield

A game for the pen of a plotter. Diatoms drift through a lit circle under the microscope. Loop your line around them to catalogue them, and keep your ink from running dry.

§1 · Play

Score
0
Slide
1
Best
0
Ink

How to play

  1. Your pen never stops. Steer it with ◀ ▶, or point where it should go.
  2. When your line crosses itself, the loop closes and catches every diatom inside. Catch several at once and they multiply, in points and in ink.
  3. Your ink drains all the time, and the rim costs a little. Keep your pen, and the wet ink just behind it, clear of the amber contaminants.

Loop your ink around diatoms to catch them: the more in one loop, the more points and ink. Keep the amber contaminants off your pen and its wet ink. Hold a finger where the pen should go, or use ◀ ▶.

§2 · How it plays

One line, drawn

The pen never stops. You only steer it, and it leaves wet ink behind. When the line crosses itself it closes a loop, and every diatom inside the loop is caught. A loop around several at once scores their points times their number, so five small diatoms beat one large one many times over. A bigger loop takes longer to close, though, and if the line snaps first, the whole loop is lost.

Each catch refills your ink, and the ink drains all the time. Amber contaminants drift in and drift towards you. The newest stretch of your line, just behind the pen, is still wet and drawn bright. If a contaminant touches it, the line snaps and you start again. Further back the ink has set, and contaminants drift over it without harm, though a loop can still close across it. If one touches the pen, the run is over. The field gets busier the longer you last. Every 500 points fills a slide, and the counter above the field keeps count.

§3 · Specimens

Glass in the water

Diatoms are real, and there are a great many of them. They are single-celled algae that live in almost any water with light in it. Each one builds its cell wall from silica, the stuff of glass, in two halves that fit together like a box and its lid. By common estimates, diatoms do about a fifth of all the photosynthesis on Earth.

Their walls are patterned with rows of pores so fine and so regular that nineteenth-century microscopists used them to test lenses. A lens that could resolve the markings on Pleurosigma angulatum was a good one. The four in the game are real genera, drawn simply: Coscinodiscus, a round disc; Navicula, whose name means "little ship"; the three-cornered Triceratium; and Asterionella, whose cells join at one end to make a star.

Darkfield is one way to look at them. A stop in the condenser blocks the direct beam, so only light the specimen scatters reaches the objective, and the glass walls shine against black. That is the look the game borrows.