if(col.numCells()==1) //special case for 1-cell
rad2sqrt = _colRadius-(_colRadius/3);
for(int i=0; i<col.numCells(); ++i) {
Cell cell = col.getCell(i);
Point center = getCellPos(cell);
if(_mousePos.x > center.x-rad2sqrt && _mousePos.y > center.y-rad2sqrt) {
if(_mousePos.x < center.x+rad2sqrt && _mousePos.y < center.y+rad2sqrt)
return cell;
}