The diagram shows the field lines near the poles, X and Y, of two magnets.
 At left a rectangular box with the long horizontal side labeled X. At right a rectangular box with the long horizontal side labeled Y. There is a gap between the boxes. Curved lines with arrowheads emerge from the right end of X and the left end of Y and point up and down.
 Based on the field lines, what are the poles of the magnets?
 X: north
 Y: south
 X: south
 Y: north
 X: north
 Y: north
 X: south
 Y: south