v4 = <2, 2>
m3 = <<3, 1>, <-1, -3>>
m4 = <<8, 5>, <20, 13>>
m6 = <<-2.0, 1.0>, <1.5, -0.5>>
m7 = <<1, 2>, <3, 4>>
m8 = <<-2, 1>, <3/2, -1/2>>
m9 = <<1, 0>, <0, 1>>
m11 = <<9, -2, -1>, <-2, 4, -2>, <-1, -2, 1>>
m12 = <<-4, 0, 0>, <0, -4, 0>, <0, 0, -4>>
det = -4