Sorry the ASCI art got mugged.

Joseph, what program do you use to read newsgroup? Could you see this:
http://home.comcast.net/~pbrett2/ventpipetwocases.jpg



CASE 1:

+---------------------------------------------+
|---------------------------------------------|
+------+----+---------------------------------------------|
|IIIIIIIIIIIIIIII|----------------------------------------|
|IIIIIIIIIIIIIIII|----------horizontal-pipe---------------|
+IIIIIII----+---------------------------------------------|
|IIIIII| |---------------------------------------------|
|IIIIII| +---------------------------------------------+
|IIIIII| out
|IIvIII| of
|IIeIII| the
|IIrIII| house
|IItIII|
|IIIIII|
+-----+IIIIII+
|IIIIIIIIIIII|
|IIIIIIIIIIII|
+-----+------+
To Dryer

CASE 2:


*----------------------------------------+
/-----------------------------------------|
/------------------------------------------|
*II*----------------------------------------|
|III\---------------------------------------|
|IIII\--------------------------------------|
|IIIII\+------------------------------------+
|IIIIII|
|IIIIII|
|IIIIII|
|IIIIII|
|IIIIII|
|IIIIII|
|IIIIII|
|IIIIII|
+IIIII+IIIIII+
|IIIIIIIIIIII|
|IIIIIIIIIIII|
+-----+------+

To Dryer