**find longest horizontal lines:

hmax_1 = 0;
hmax_2 = 1;
i = 0;
SHAVEVEC_ITERATE(lines, LineData, ln)
	if (LineData::isHorizontal()(ln)) {
		if (LineData::LengthGreaterThan()(ln, lines[max_1])) {
			hmax_2 = hmax_1;
			hmax_1 = i;
		}
		else if (LineData::LengthGreaterThan()(ln, lines[max_2])) {
			hmax_2 = i;
		}
		i++;
	}
}

** find longest non-horizontal lines

vmax_1 = 0;
vmax_2 = 1;
i = 0;
SHAVEVEC_ITERATE(lines, LineData, ln)
	if (!LineData::ParallelTest()(lines[hmax_1], ln)) {
		if (LineData::LengthGreaterThan()(ln, lines[vmax_1])) {
			vmax_2 = vmax_1;
			vmax_1 = i;
		}
		else if (LineData::LengthGreaterThan()(ln, lines[vmax_2])) {
			vmax_2 = i;
		}
		i++;
	}
}

** construct boundary lines
*** left:
find leftmost endpt of two horiontal lines
find leftmost ln of two vertical lines
contruct infty line thru endpt at orientation of ln

*** right:
find righttmost endpt of two horiontal lines
find righttmost ln of two vertical lines
contruct infty line thru endpt at orientation of ln

*** top:
find topmost endpt of two vertical lines
find topmost ln of two horizontal lines
contruct infty line thru endpt at orientation of ln

*** bottom:
find bottommost endpt of two vertical lines
find bottommost ln of two horizontal lines
contruct infty line thru endpt at orientation of ln

** construct sketches for each grid square
*** example: middle
leftHalfPlane(vert2) && rightHalfPlane(vert1) 
	&& bottomHalfPlane(horiz1) && topHalfPlane(horiz2)

** find bottom blue and pink pixels:
sk & !sk[*camSkS.idxS]

** calculate contents of each board pos:
for each grid square sketch
	if !NEW_SKETCH(sq & bluebottoms)->isEmpty() mark sq blue
	else if !NEW_SKETCH(sq & pinkbottoms)->isEmpty() mark sq pink
	else mark sq empty