Logic Masters Deutschland e.V.

Lupin's Loop 4

Sorrounded

Backstory

The island bomb destroyed the aliens’ monitoring system, and for one brief moment, everyone believed Earth was saved.

Little did they know, it was only the beginning.

As the smoke cleared, a hidden staircase appeared beneath the ruins, descending to the edge of a vast underground city the aliens had built thousands of years ago. The monitoring system had not been the true danger. It had only been guarding the entrance.

At the center of the city stood a control chamber containing the aliens’ greatest secrets. Lupin had to reach it quickly and take the data before the city collapsed.

But the chamber was impossible to reach on foot. The only way in was through the old alien metro system, which had been damaged by the explosion. To reach the center, Lupin had to redesign it as two separate rings: a large outer loop serving the edge of the city, and a smaller inner loop serving the center.

The city was falling apart, and with it, humanity’s only chance to understand its enemy.

Rules

Normal Sudoku rules apply.

Greater Than: A greater than symbol points towards the smaller number.

Metro Lines: Draw two metro lines that travel orthogonally from cell to cell, never branching, crossing, or overlapping, either with themselves or with each other, and eventually close into two loops.

Walls: Thick black walls cannot be crossed by the loops.

Sorrounded: One loop must lie entirely inside the other, so the outer loop completely surrounds the inner loop.

Stations: Every station must lie on a loop. A digit in a station equals the total number of stations containing that digit.

Parity: All cells on the same loop share the same parity. The two loops may have the same or different parities.

Red Sensors: A digit in a red sensor equals the number of cells visited by either loop in the 3×3 box centered on that cell.

Mirror Cell: The mirror cell has mirrored parity, meaning its parity is considered to be the opposite of its real parity. If a loop passes through it, treat the cell according to this mirrored parity.

Solve Online

This is the fourth puzzle in the Lupin’s Loop series, and I truly hope you enjoy solving it. I would be very happy to hear any feedback, thoughts, or comments you may have.