dude is -2m/s, ...ettte is +2m/s
pos vel is when dudette, eg, is going in increasing x, in this case.
neg vel is when dudette, eg, is going in decreasing x, in this case. ie she turns round and runs
zero vel is zero speed. dudette standing still
positive vel neg pos top dia
no
yes
yes
yes
yes
yes
all yes looks like ...
