The syntax of GS is modeled on the page markup language LaTeX that is heavily used by professional scientists and mathematicians. LaTeX is capable of producing virtually anything that could reasonably be considered character-based information such as text, equations, and tables. Since GS is syntactically equivalent to LaTeX, it provides an equivalent linear representation of that character-based information.
GS symbols are expressible in a "building block" notation that uses approximately 200 building blocks. The most common symbols are single building blocks but multiple building block symbols are required to define the thousands of exotic symbols used by professional scientists. The building block philosophy includes the ability to extend GS to incorporate author-defined symbols - a critical requirement if a language is to be rich enough to express future literature as well as literature of the past.
Gardner and Salinas have defined braille symbols for these building blocks that are as close as possible to common braille. The result is a grade 1 unified GS braille representation. Symbols that cannot be expressed as a single six dot braille cell have both a six dot and eight dot braille representation. [Eight dot braille cells have four rows of two columns.]
The lower case letters and common punctuation marks are defined to conform to standard English braille. Other common symbols such as the number (#) sign and the ampersand (&) sign are assigned braille patterns that are intuitive to present braille users. A six dot GS capital letter is a dot-6 followed by the lower case letter - the same convention used in English literary braille. The eight dot capital letter is the lower case cell with a dot-7 (an extra dot on the lower left). This is the common representation for capital letters in all eight dot braille codes. Six dot braille representations for many other common symbols such as parentheses, the plus, times, equals signs, are adopted from the unified braille code.
The greatest departure from common braille practice is the assignment of numbers. In literary braille numbers are represented by letters in a "number mode" started by a braille number indicator. This practice dates to Mr. Louis Braille, and in the opinion of many observers is the most serious error Mr. Braille made. European math codes also (sometimes) represent numbers by this numbr mode, but the American Nemeth math code and all computer braille codes assign unique braille symbols to numbers.
Historically the development of GS began when the ubc committee on a close vote decided to adopt the literary braille number mode convention. Gardner and Salinas were convinced that this damned the ubc never to be a usable code for any but the simplest literature and began development of an alternative. They adopted the European computer braille definitions for GS numbers. These have proven relatively easy for Europeans to learn, and Americans who have learned these numbers often adopt them in preference to other forms.
Many GS building blocks have double cell definitions in six dot braille and single cell definitions in eight dot braille. The eight dot representations are related by transformation rules that depend on the first cell (which must be one of five "prefix" cells) of the six dot symbol. For example, the transformation rule for symbols in which the six dot prefix cell is dot-6 is: the eight dot cell is the same as the six dot second cell except that a dot 7 is added.
Most braille readers are likely to find the six dot representation perfectly satisfactory, but the compact 8 dot representation may be preferred by some, particularly people using on-line computer braille displays.