Code Sketch

// polar bear - using pic.thatsXX transforms
// works with Kojo 2.9.18 and later

// This program uses image PB1.png, which is available at:
// https://drive.google.com/file/d/1mqSthvmWl7nE8WidgU9YKaPHFsx3nEvQ/view

// Download the above image and put it in your Downloads folder
// before running the code

def mountain(n: Int) = Picture {
    beginShape()
    curveVertexRt(-300, 0)
    curveVertexRt(-300, 0)
    curveVertexRt(n, 100)
    curveVertexRt(n, 0)
    curveVertexRt(n, 0)
    endShape()
}

def mountains(n: Int, size: Double): Picture = {

    if (n == 1) {
        mountain(150)
            .withFillColor(mountainclr)
            .withPenColor(noColor)
    }

    else {
        picStack(
            mountain(120)
                .withPenColor(noColor)
                .withFillColor(mountainclr),
            mountains(n - 1, size)
                .thatsTranslated(200, 0)
        )
    }
}

cleari()
val assetsDir = "~/Downloads"
val bg = Picture.image(s"$assetsDir/PB1.png")
val PB1 = trans(-1000 + 190, -550) * scale(2) -> bg
val sky = cm.linearGradient(0, 100, ColorMaker.hsl(201, 0.59, 0.94), 0, 200, ColorMaker.hsl(240, 1.00, 0.78), false)
val sunclr = cm.radialGradient(0, 0, cm.white, 70, ColorMaker.hsl(240, 1.00, 0.78), false)
val sunclr2 = cm.radialGradient(0, 0, cm.white, 70, ColorMaker.hsl(194, 0.43, 0.71), false)
val mountainclr = cm.linearGradient(-55, 40, ColorMaker.hsl(120, 0.22, 0.89), 0, 0, ColorMaker.hsl(120, 0.06, 0.52), false)
val pic = picStack(
    Picture.rectangle(850, 380)
        .thatsTranslated(-300, -380)
        .withPenColor(noColor)
        .withFillColor(ColorMaker.hsl(194, 0.43, 0.71)),
    Picture.rectangle(850, 380)
        .thatsTranslated(-300, 0)
        .withPenColor(noColor)
        .withFillColor(sky),
    mountains(3, 10)
        .thatsTranslated(0, -4)
        .withPenColor(noColor)
        .withPenThickness(0)
        .withBlurring(30)
        .withFading(110)
        .withFlippedY,
    Picture.circle(75)
        .withPenColor(noColor)
        .thatsTranslated(0, 239)
        .withFillColor(sunclr2)
        .withFading(220)
        .withFlippedY,
    Picture.circle(75)
        .withPenColor(noColor)
        .thatsTranslated(0, 270)
        .withFillColor(sunclr),
    mountains(3, 10),
    PB1
)
drawCentered(pic)