Heyawake

Description
Heyawake is a binary determination puzzle in which the cells in a grid are split into either shaded or unshaded.

Rules
The objective is to shade some cells, subject to the following rules:


 * 1) Numbers indicate how many shaded cells are in a room.
 * 2) Shaded cells must never touch horizontally or vertically.
 * 3) Unshaded cells must form one, connected area.
 * 4) A straight line of unshaded cells can only connect two rooms, a line of white cells which connects three or more rooms is not allowed.

Example
A standard 10x10 heyawake and its solution.



Variants
Unless otherwise indicated, standard heyawake rules apply to all variants.

Heyawaky: A straight line of unshaded cells can only cross over one border at the most, even if it would re-enter a room.

Heyawake Symmetry: Instead of clue numbers, clues indicate whether the pattern of shaded cells has 180° symmetry within a room or not.

Heyawake Twin: Shaded cells share an edge with exactly 1 other shaded cell.