Also, if why are you using .tx(...) if your neighborhood lookup is *not* toroidal? > mySpace.getVonNeumannNeighbors(myX, myY, 1, Grid2D.BOUNDED, false, vNObjects, xNeighbors, yNeighbors); Beyond this, I can't help you much, you'd need to provide a significantly more precise description of your problem. > On Jul 30, 2015, at 10:23 PM, Sean Luke <[log in to unmask]> wrote: > >> This doesn't look right. >> >> On Jul 30, 2015, at 9:16 PM, Stewart Aitken <[log in to unmask]> wrote: >> >>> nextY = mySpace.tx(yNeighbors.get(i)); >