Code Sketch

clear()
setBackground(white)
setSpeed(superFast)
setPenColor(gray.fadeOut(0.5))
setPenThickness(1)

def polygon(n: Int) {
    var len = 30
    if (n <= 4) {
        len = len + 20
    }
    repeat(n) {
        forward(len)
        right(360.0 / n)
    }
}

val nx = 15
val ny = 15
val cb = canvasBounds
val dx = cb.width / nx
val dy = cb.height / ny

def shape() {
    savePosHe()
    val a =  random(-10,10)
    val r = random(3, 9)
    right(a)
    polygon(r)
    restorePosHe()
}

def posx(gx: Int) = cb.x + gx * dx
def posy(gy: Int) = cb.y + gy * dy

def block(gx: Int, gy: Int) {
    setPosition(posx(gx), posy(gy))
    setFillColor(randomColor.fadeOut(0.8))
    shape()
}

repeatFor(0 until nx) { x =>
    repeatFor(0 until ny) { y =>
        block(x, y)
    }
}