transposeIntoArray method
Implementation
Matrix3 transposeIntoArray(List<num> r) {
final m = elements;
r[0] = m[0];
r[1] = m[3];
r[2] = m[6];
r[3] = m[1];
r[4] = m[4];
r[5] = m[7];
r[6] = m[2];
r[7] = m[5];
r[8] = m[8];
return this;
}