Barrier LITS is a variant of LITS, in which the cells in a grid are split into either shaded or unshaded.


The objective is shade four connected cells in each shape, subject to the following rules:

  1. No two of the same tetrominos, including rotations / reflections are allowed to touch.
  2. All shaded cells must connect upon completion.
  3. No 2x2 area of shaded cells is allowed.
  4. Some shapes include barriers between cells, tetrominos are not allowed to appear on both sides of the barrier.


A standard 10x10 Barrier LITS and its solution.

Barrier LITS Example
Barrier LITS Solution