The Doppit Almanac · No. 12

Pipeit, a daily pipe loop puzzle

Rotate pipes into one closed loop

What it is

Pipeit is Doppit's plumbing job, a rotation puzzle from the family known elsewhere as Pipes or Net. Every cell holds a scrap of pipe, delivered spun the wrong way. You turn the pieces until the whole board joins into one connected network, with every opening answered and nothing aimed at the walls.

Gold flow spreads from the top-left pipe as you work, so you watch the network come alive one joint at a time. You can read the best moves before you tap them: a bent pipe in a corner has exactly one turn that keeps both its openings on the board, and every joint you settle narrows the choices next door.

How it plays

The plumber's contract is brief.

• Tap a pipe to turn it a quarter clockwise.
• Every opening must meet an opening next door. A closed side answers nothing.
• No pipe may ever point off the board. A leak rings its cell red.
• You win when the gold flow reaches every cell on the board.

The difficulties

Three jobs are booked daily. Expert is the fourth, never booked, always open to practise on. Easy is six cells square and sealed in thirty seconds to a minute. Medium is eight square and takes one to three minutes of patient turning. Hard is twelve square, a three-to-six-minute tangle of elbows and tees. Expert is fourteen square, a third again as many pieces as hard, and its floor is a hundred and fifty-two turns. A new board is laid every day, and it costs nothing.

Nearby in the almanac: Trackit, Snipit and Yinit