fun double(x: Int): Int {
    return 2*x
}
val x = 23

"hello, " + double(3) + x

val numbers: MutableList<Number> = mutableListOf(1, 4, 3)
val line = Line()
line.setY(numbers)
val plot = Plot()
plot.setTitle("Kotlin Plotting")
plot.add(line)
plot