I love the sheer elegance of F#

matrix.fs

module Math
  type Matrix = 
      | Matrix of decimal [,]
      static member create l = Matrix l
      
      member this.elements = 
          match this with
          | Matrix l -> l

      member this.rowcount = this.elements |> Array2D.length1
      member this.columncount = this.elements |> Array2D.length2
      
      member this.Item 
          with get (r, c) = this.elements.[r, c]
          and set (r, c) value = this.elements.[r, c] <- value
      
      static member zero n m = Array2D.create n m 0M |> Matrix.create

      static member vector x y z = [[x];[y];[z];[1M]] |> array2D |>  Matrix.create 
      
      static member unit n = 
          let result = Matrix.zero n n
          [ for i in 0..n - 1 -> result.[i, i] <- 1M ]
          |> ignore
          result
      
      static member (+) (l : Matrix, r : Matrix) = 
          let result = Matrix.zero l.rowcount l.columncount
          [ for i in 0..(l.rowcount - 1) -> 
                [ for j in 0..(r.columncount - 1) -> result.[i, j] <- l.[i, j] + r.[i, j] ] ]
          |> ignore
          result
      
      static member (*) (l : Matrix, r : Matrix) = 
          let result = Matrix.zero l.rowcount r.columncount
          [ for i in 0..(l.rowcount - 1) -> 
                [ for j in 0..(r.columncount - 1) -> 
                      [ for k in 0..(l.columncount - 1) -> result.[i, j] <- result.[i, j] + l.[i, k] * r.[k, j] ] ] ]
          |> ignore
          result
      
      static member rotationAroundX (theta:decimal) = 
          let sin = theta |> double |> System.Math.Sin  |> decimal
          let cos = theta |> double |> System.Math.Cos  |> decimal
          [ [ 1M; 0M; 0M; 0M ]
            [ 0M; cos;-sin; 0M ]
            [ 0M; sin; cos; 0M ]
            [ 0M; 0M; 0M; 1M ] ]
          |> array2D
          |> Matrix.create
  
      static member rotationAroundY (theta:decimal) = 
          let sin = theta |> double |> System.Math.Sin  |> decimal
          let cos = theta |> double |> System.Math.Cos  |> decimal
          [ [  cos ;0M ;sin ; 0M ]
            [ 0M; 1M; 0M; 0M ]
            [ -sin; 0M; cos; 0M ]
            [ 0M; 0M; 0M; 1M ] ]
          |> array2D
          |> Matrix.create

      static member rotationAroundZ (theta:decimal) = 
          let sin = theta |> double |> System.Math.Sin  |> decimal
          let cos = theta |> double |> System.Math.Cos  |> decimal
          [ [ cos; -sin; 0M; 0M ]
            [ sin; cos;0M ; 0M ]
            [ 0M; 0M; 1M; 0M ]
            [ 0M; 0M; 0M; 1M ] ]
          |> array2D
          |> Matrix.create

      static member translation x y z =
          [ [ 1M;0M;0M;x]
            [ 0M;1M;0M;y]
            [ 0M;0M;1M;z]
            [ 0M;0M;0M;1M] ]
          |> array2D
          |> Matrix.create