BP1206 is the same solution but using the vertical axis instead of the horizontal axis.

BP1215 is the same solution but with the NW/SE diagonal instead of the vertical axis.

BP1206 is the same but using "vertical" instead of "horizontal".

Horizontal axis of symmetry vs. no horizontal axis of symmetry.

BP1206 is the same using "vertical" instead of "horizontal".

Aaron David Fairbanks