Code Sketch

// Mountain reflection usingregular picture transforms and a rondom seed
size(780, 660)
cleari()
zoom(1.005)
setBackground(black)
initRandomGenerator(-3846417674807362996L)

//Background
val bgColor = cm.linearGradient(0, 0, Color(44, 185, 255), 0, cheight, ColorMaker.hsl(0, 0.40, 0.50), false)
val bg = fillColor(bgColor) * penColor(noColor) * trans(0, cheight / 2) -> Picture.rectangle(cwidth, cheight / 2)

//Mountains
val mountain = Picture.fromVertexShape { s =>
    import s._
    beginShape()
    curveVertex(0, 0)
    curveVertex(0, 0)
    curveVertex(20, 25)
    curveVertex(45, 43)
    curveVertex(65, 45)
    curveVertex(100, 30)
    curveVertex(150, 0)
    curveVertex(225, 50)
    endShape()
}

val mColor = cm.linearGradient(0, 0, ColorMaker.hsl(35, 0.76, 0.05), 100, 50, cm.hsl(35, 0.75, 0.30), false)
val mRevColor = cm.linearGradient(0, 0, cm.hsl(35, 0.75, 0.30), 100, 50, ColorMaker.hsl(35, 0.76, 0.05), false)

def mountains(n: Int): Picture = {
    val mtn = if (randomBoolean)
        penColor(darkGray) * fillColor(mColor) -> mountain
    else
        penColor(darkGray) * fillColor(mRevColor) * flipY * trans(-100, 0) -> mountain

    if (n == 1) {
        mtn
    }
    else {
        picStack(
            mtn,
            trans(85, 0) -> mountains(n - 1)
        )
    }
}
//Mountains

//Moon
val moon = penColor(noColor) * fillColor(cm.silver) -> Picture {
    forward(50)
    right(90)
    right(90, 50)
    right(90)
    forward(50)
}
//Moon

//Birds
def bird(s: Double) = penColor(black) -> Picture {
    right(90)
    right(60, s)
    left(120)
    right(60, s)
}
def birds(n: Int, s: Double): Picture = {
    if (n == 1) {
        bird(s)
    }
    else {
        picStack(
            bird(s),
            trans(50, s * 0.6) -> birds(n - 1, s * 0.8)
        )
    }
}
//Birds

//Moonlight
val moonLight = distantLight(215, 5)
//Moonlight

val pic1 = picStack(
    bg,
    trans(cwidth, cheight) * rot(180) -> moon,
    trans(cwidth / 2 - 50, cheight / 2 + 100) -> birds(8, 50),
    trans(0, cheight / 2) -> mountains(9)
)

val pic = effect(moonLight) -> picStack(
    penColor(noColor) * fillColor(Color(44, 185, 255, 100)) * trans(0, cheight / 2 - 25) ->
        Picture.rectangle(cwidth, 50),
    pic1,
    flipX * trans(0, -cheight + 3) * fade(400) * blur(20) ->
        pic1
)

draw(trans(-cwidth / 2, -cheight / 2) -> pic)