My idea is this: when crafting certain objects (my example for this will be the Express, Fast, and Normal Transport Belts) you sometimes need lower-tier objects, such as when crafting the Express Transport Belts you need Fast Belts and for that you need Normal Belts. My idea is a half- built object- it can't be placed anywhere except on the object it's missing. For instance, if you have a Transport Belt you want to upgrade to a Fast Transport Belt, instead of crafting all the Transport Belts before the fast belt, you can just place the half-built one on it- this would make upgrading Transport Belts or Inserters much faster. If you have any ideas how this could be made better, please comment!
-spenmich
