In the online article about static variables at
http://arduino.cc/en/pmwiki.php?n=Reference/Static
I caught an error or at least a misleading comment in the bottom part about "reflecting the position" if the "random walker" oversteps a border.
The current statement is:
if (place < randomWalkLowRange){ // check lower and upper limits
place = place + (randomWalkLowRange - place); // reflect number back in positive direction
}
else if(place > randomWalkHighRange){
place = place - (place - randomWalkHighRange); // reflect number back in negative direction
}
But this will only keep the position at the border which has been overstepped instead of reflecting the direction of travel for excess steps.
To really deflect the walking direction once the limits are reached, the following formulas have to be used:
place = randomWalkLowRange + (randomWalkLowRange - place); //reflect in positive direction
place = randomWalkHighRange - (place - randomWalkHighRange); //reflect in negative direction
Please correct the wiki - or me, if I made a big error in my thinking.