- pointing-up? v <vectr>procedure
- pointing-down? v <vectr>procedure
- pointing-left? v <vectr>procedure
- pointing-right? v <vectr>procedure
- horizontal? v <vectr>procedure
- vertical? v <vectr>procedure
Procedures returning booleans based on the "direction" of v as if it were to be drawn moving from its head to its tail on a standard Cartesian coordinate graph where positive x grows to the left and positive y grows up.