Small Mind Games

Nurimaze ("Nurimeizu") consists of a grid divided on regions. The aim is to blacken some regions according to the following rules:
- Cells with letters, circles or triangles are always white.
- White cells form a path from a cell with S ("start") to a cell with G ("goal"); a path must be exactly one cell wide.
- A path from S to G includes all cells with circles and no cells with triangles.
- No 2 x 2 cell area within the grid can have the same color.
- All white cells must form an orthogonally continuous area.
- White cells must not form a loop.