Boyd's syllabic shorthand is a system of shorthand invented by Robert Boyd, published originally in 1903, and updated in 1912. In this system, symbols are distinguished both by orientation and by shape, with the shape representing the vowel and the orientation the consonant. Thus, "ab" and "am" would be represented by the same shape of mark (in this case an L-shape), oriented differently; and "ab" and "eb" would be represented by differently shaped marks, oriented the same way.

More information on the Wikipedia page [1].

It can be downloaded here [2].