Featured Puzzle: Alternate Corners #3

Draw a single loop which passes through every cell of the grid. Naturally, you have a few restrictions:

• You must make a 90-degree turn when passing through a cell containing a circle.
• While traveling between circles, you must make exactly one 90-degree turn.
• All lines must move in orthogonal directions, connecting the centers of adjacent cells.
• The solution has only one loop, which may not cross itself.