#description of an array of 14*11 vents

!cnt 14 11 | rcalc -o vent.fmt -e 'xstart=$1*2.875;zstart=$2*.5' | xform -t 4 0 3.75

void polygon vent_frame
0
0
30
	0	0	0
	0	0	10.5
	48	0	10.5
	48	0	0
	4	0	0
	4	0	3.25
	44.375	0	3.25
	44.375	0	8.375
	4	0	8.375
	4	0	0

