def _box(h, w):
"""
A sequence of points representing the four corners of a board of height *h* and
width *w* positioned at (0, 0) and in the first quadrant.
"""
return [ homogenous( 0, 0),
homogenous(w-1, 0),
homogenous(w-1, h-1),
homogenous( 0, h-1) ]
def _board(h, w):
"""
A sequence of points representing all corners (by row) on a board of height *h*
and width *w* positioned at (0, 0) and in the first quadrant.
"""
return [ homogenous(x, y) for y in range(h) for x in range(w) ]