Pentomino Rooms (509)

Place identical pentominoes (consisting of 4 line segments) into the gridlines. The pentominoes may be rotated and reflected, but they cannot touch each other, not even at point. Each grid cell represents a room. Dividing walls are to be placed in the grid such that all clue numbers represent the number of rooms which can be seen in any of the four directions from that location, not counting the room the clue number is in. Dividing walls must be formed exclusively of identical pentomino shapes which must lie along the grid lines and must not touch each other even at a corner. No part of a pentomino may lie along the outer perimeter of the grid: nor may a pentomino touch the perimeter at more than one point.

Reference: WPC 2016 (65)