Better matrix - but it crashes the pretty printer in FSI

Better.fs

    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 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

fsi.fsx

//works:
(Matrix.unit 3).elements;;
//crashes fsi pretty printer:
Matrix.unit 3