(a) in writing;
(b) signed by the testator or in the testator's name by some other individual in the testator's conscious presence and by the testator's direction; and
(c) signed by at least two individuals, each of whom signed within a reasonable time after having witnessed either the signing of the will as described in subsection (1)(b) or the testator's acknowledgment of that signature or acknowledgment of the will.
(2) A will that does not comply with subsection (1) is valid as a holographic will, whether or not witnessed, if the signature and material portions of the document are in the testator's handwriting.
(3) Intent that the document constitute the testator's will may be established by extrinsic evidence, including, for holographic wills, portions of the document that are not in the testator's handwriting.