add 'notes'

_data/assets.yml

@@ -4,6 +4,7 @@
   images: ['gen/main.png']
 
 - name: Big Featureless Cube
+  notes: "Choice of red color is not well motivated, it was just a chance to send a string as an OpenSCAD parameter.  This color is _NOT_ carried through to the STL viewer, because OpenSCAD STLs do not carry color information.  Since models are zoomed, you can't see the size difference either.  Whoops."
   scad: main.scad
   flags: -Dsize=100 -Dcolor="red"
   stl: gen/big.stl

index.md

@@ -26,6 +26,8 @@ Sections to consider adding:
 
 {% for asset in site.data.assets %}
   - {{ asset.name }}:
+
+      {{ asset.notes }}
   {% if asset.scad %}
   {% assign basename = asset.scad | split: "/" | last %}
     - [{{ basename }}](resources/{{ asset.scad }})