In the December 18, 2003 posting in the Spatial Locations thread, the meaning of Ex. 1g (my Ex. c below) was not explained. Following is a clarification of that and other indications in which an ad. lib sign is used in connection with a direction sign.

Ex. a) Any forward level, e.g., forward low, forward middle, or forward high.
Ex. b) Approximately forward (level unspecified), e.g., slightly left or right of forward.
Ex. c) Any of the three levels (as in Ex. a), which can deviate (as in Ex. b).
Ex. d) Any position close to the right or left of forward middle, but not above or below forward middle, because the level has been stated.