Describe the feature

a pane that can fill that gab (picture) to be a window. and one for slope roofs. maybe one for 2 by 1 block slopes

I like the idea, but it'll likely be a while til this is added because I need to find a way to handle occlusion between these blocks, otherwise placing multiple of them next to each other will look awful (imagine like placing multiple vanilla glass blocks next to each other and the faces between them are visible).