1 - Single - Replace one glyph with one glyph 2 - Multiple - Replace one
glyph with more than one glyph 3 - Alternate - Replace one glyph with one
of many glyphs 4 - Ligature - Replace multiple glyphs with one glyph 5 -
Context - Replace one or more glyphs in context 6 - Chaining - Context
Replace one or more glyphs in chained context