The Doppit Almanac · No. 18

Springit, a daily spring placement puzzle

Place springs so water soaks everything

What it is

Springit, No. 18, is the almanac gone damp: a house original about water and where to let it out of the ground. The board is a landscape, every cell marked with its height in shade and numeral, and all of it is thirsty. You open springs until every last square is soaked.

Water obeys the survey. It flows to side neighbours at equal or lower height, and it gives out two squares from home. Coverage must be exact, which is where the placing turns delicate.

How it plays

Water rights here are precise.

• A spring soaks its own cell; water spreads only to side neighbours of equal or lower height, never uphill.
• Water runs two squares from its spring, then gives out.
• Every cell drinks from exactly one spring. Ground watered twice is as wrong as ground left dry.
• Springs never touch: no spring may stand in the eight cells around another.
• An edge number counts the springs in its row or column; a blank edge keeps its count to itself.

The difficulties

The survey runs at four depths. Easy soaks through in thirty seconds to a minute. Medium wants one to three minutes of contour reading. Hard takes three to six, on ground that argues with the map. Expert is a practice tier on hard's own thirteen by thirteen, and it asks one move more: put a spring on a cell, play out every dot and every spring that forces, and find a board that can never be finished. A new landscape is charted every day, at no charge.

Nearby in the almanac: Wellit, Aquait and Islandit