This mod adds stained glass varieties for aesthetic purposes.
Also it introduces several pane varieties (glass, obsidian, iron bars) for completeness' sake.
The stained glass types are made by arranging various dyes around a glass block in a pattern. In total, there are 12 color schemes.
Furthermore, combining several of individual stained glass panes produces shaped pieces (double, triple/L-shaped, quadruple/2x2, noncuple/3x3), where all but one of the nodes can noclip through solid objects. This is meant to be used with non-rectangular window frames, allowing to fill them in without gaps.
The recipes literally follow the shapes they create:
double: X X triple: X XX quadruple: XX XX noncuple: XXX XXX XXX where X is the given pane type
The combined pieces can always be broken down into the constituent individual panes.