Rules: The challenge is to draw a loop around the grid, subject to the following rules:
- White circles must be travelled straight through and must turn in the previous and/or next cell in its path.
- The loop must turn in black cells and must travel straight through the next and previous cells in its path.
- The loop mustn't cross or branch off.
- All gates must be travelled straight through exactly once without any turns.
- Some gates and circles are numbered and must be passed in sequence, according to the number of the gate.