Signpost LITS Instructions

Rules: The challenge is to shade four connected cells in each region, 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 cells include a letter. If the corresponding cell is shaded then the tetromino must match the letter.