is_lower_triangular_matrix.rb

def isLowerTriangularMatrix(matrix)
    x = 0
    y = 0
    starting = 1
    result = true

    while (x < matrix.length)
          y = starting

          while (y < matrix.length)
                if matrix[x][y] != 0 then
                   result = false
                end

                y = y + 1
          end

          starting = starting + 1
          x = x + 1
    end

    return result
end