toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() => '''
[ $a, $c, $e ]
[ $b, $d, $f ]
[ 0.0, 0.0, 1.0 ] // _m4_10 = $_m4_10
''';