Below is the grid for Bliss symbols, modified from Blissym Code for Information Interchange from Douglas Crockford that describes how the Blissym.ttf fonts are built and from the official fundamental rules of Blissymbolics: creating new Blissymbolics characters and vocabulary
|tall indicator limit|
|middle sky line||Bliss Unit||Sky Zone|
|middle earth line||Earth Zone|
Normal Blissymbols are formed between sky line and earth line The earth line is the text base line. The sky line is placed around the same height as upper case letters. The distance between the earth line and sky line is one unit. The space is divided in half by a middle line, and into quarters by the middle sky line and the middle earth line.
Above the skyline we can find 2 lines for indicators. Most indicators should hang form the indicator limit. Below the earthline is a space for so-called descenders, e.g. the root of an onion.
The lines form the boundaries of three half unit high zones, the sky zone, middle zone, and earth line. There is also an ultra zone which is used to hold the grammatical indicators. The ultra zone and infra zone also are the homes of two SEMI elements.
The space is further divided horizontally at quarter unit intervals.