vertWarning method
aBox calls warnings in case of over-length-width box in matrix. Set vertical Warning-line for over-sized-box to screen matrix
Implementation
void vertWarning(int _x, _y, count, String _s) {
String _newS;
int toX = 0;
// howTo NULL cast it to int.. yes, WORKS
toX = (_x + count).toInt();
for (var x = _x; x < toX; x++) {
_newS = tl.changeLetter(_matrix[x], _y, _s);
_matrix[x] = _newS;
}
}