fix spacing, crosslinks, shorten threshold

_pages/air.md

@@ -286,12 +286,12 @@ I built silencers into window recesses on two occasions. They were simpler and m
 
 The design below is a zig-zag channel through insulation inside a wooden box with a hole at each end. Each hole has 4 possible locations: face, sides, or end. Cut a circle for ducting or fan, a slot for a universal vent. The fan mount adapts to all 4 locations, inside or out.
 
-The box is lined with porous non-toxic insulation. clean wool, shredded fabric, wood fiber could all work. Note, the shredded fabric and wood fiber I've tried had faint smells that I disliked. 
-
 ![plan: silencer](/img/plan/image/silencer.png)
 
 plan: silencer - [download](/img/plan/silencer.pdf)
 
+The box is lined with porous non-toxic insulation. clean wool, shredded fabric, wood fiber could all work. Note, the shredded fabric and wood fiber I've tried had faint smells that I disliked. 
+
 Rockwool works. It is unpleasant to work with, but it is fairly odorless. Polyester pillow filling and quilt batting and acoustic foam work. But I don't like my air going through plastic.
 
 Fiberglass is terrible to work with and often smells of chemicals. Closed cell foam, like styrofoam, polyisocyanurate boards, camping pads, etc, does not work due to non-porosity.

_pages/darkness.md

@@ -244,8 +244,8 @@ plan: double-blind with vent - [download](/img/plan/double-blind-vent.pdf)
 	- black-white
 		- laminated agricultural plastic. Called "light deprivation" tarp, used in greenhouses and for "pit tarps". I once got some for free from an agricultural plastic supply house. It was the end of a 1-ton roll of 0.125mm plastic. It was still a huge amount.
 		- easiest. And it is cool. Not in temperature, but it is appealing and satisfying to use. It is technology at its best.
-	
-			It's amazing stuff. White looks good. Use one layer for traveling. Use two layers, white sides visible, for perfect darkness. 
+
+		It's amazing stuff. White looks good. Use one layer for traveling. Use two layers, white sides visible, for perfect darkness. 
 		- lumber unit covers, discarded daily at lumber yards. They are big black/white-laminated woven plastic tarps for shipping. Graphics are printed on them. Rinse or wipe clean if necessary. Find punctures and patch them. Face/put/sandwich the black sides together, making white sides visible.
 - fabric
 	- black twill or similar tight weave.

_pages/water.md

@@ -91,21 +91,21 @@ plan: toilet frame - [download](/img/plan/toilet-frame.pdf)
 	- joint is extra strong, non-planar joint (see [gridbeam.com](https://gridbeam.com))
 	- black dots indicate heads of screws. Always drill pilot holes for screws.
 	- adjust leg height to allow a 15mm space between top of bucket and underside of toilet top
+
+![plan: squatting toilet ](/img/plan/image/toilet-squat.png)
+
+plan: squatting toilet - [download](/img/plan/toilet-squat.pdf)
 
 - liner
 	- it is a skirt with no bottom, cut at floor level. Put a pan, tray, towel, or paper on the floor under the bucket to catch spills.
 	- made of thick plastic sheeting (0.15mm)
 	- fits inside frame
 	- top edges fold over horizontal frame pieces and get thumb-tacked or taped in place on outside
 	- toilet bucket goes inside
-	- cut hole **B** for return duct: 
-		- 30mm smaller than return duct to stretch and fit over it snugly
-		- so duct is 50--100mm off floor and next to a frame leg (to attach a bracket to to support duct if necessary) 
-		- hole **B** in plan is just an example: 70mm diameter hole for 100mm diameter duct
-
-![plan: squatting toilet ](/img/plan/image/toilet-squat.png)
-
-plan: squatting toilet - [download](/img/plan/toilet-squat.pdf)
+	- cut hole for return duct: 
+		- 20-30 smaller than return duct to stretch and fit over it snugly
+		- 50--100 off floor
+		- next to a frame leg, to attach a wire or bracket to support duct
 
 ### bath