1 remove acceleration according to primary school teacher.
2 unit in km/h instead of m/s according to primary school teacher.
3 further bug reduction
4 [s]axis for x is further refine to follow
xming = Math.min(x1,xmin);
xming = Math.min(x2,xming);[/s] //  for maximum view instead of autoscale which is suppose to be difficult for young minds
5 fix PY1[1] and PY2[1] at the top left corner to follow the distance of the rectangle
6 fix the time to reflect the distance as accurate as possible for given t = 0.00s
7 use // screen view
if(x1if(x1>xmax) xmax*=1.2;
if(x2if(x2>xmax) xmax*=1.2;  instead of 4
8 change context to cars (from microsoft clipart) as to travel in km/h
9 added town A and B selectable to a maximum of 10 to 1000 km to suit most problem.
10 time is input field to suit questions that require going backwards in time