string art

function setup() {
    createCanvas(400, 300);
    background("lightsteelblue");
}

function draw() {
    strokeWeight(0.5);
    numLines = 30;

    //sun beams
    strt(-width, 0, width, 2*height, 0, 0, width, 0, 20, "yellow");
    fill("yellow");
    ellipse(width, 0, 100);  //sun

    //mountains
    fill("green");
    triangle(90, 150, 20, 250, 390, 250);
    triangle(290, 150, 390, 250, 20, 250);
    stroke("green");
    line(90, 150, 20, 250);    //left mountain
    line(290, 150, 390, 250);   //right mountain
    crshtch(90, 150, 20, 250, 290, 150, 390, 250, numLines, "palegreen");
    crshtch(290, 150, 390, 250, 90, 150, 20, 250, numLines, "palegreen");

    //water
    fill("lightseagreen");
    rect(0, 250, 400, 50);
    lne(0, 250, 0, 300, 400, 250, 400, 300, 30, "blue");

}


//diag crosshatch
function crshtch(x1, y1, x2, y2, x3, y3, x4, y4, numLines, colour){
    stroke(colour);
    dx3 = (x4-x3)/numLines;
    dy3 = (y4-y3)/numLines;
    dx1 = (x2-x1)/numLines;
    dy1 = (y2-y1)/numLines;
    dx2 = (x4-x3)/numLines;
    dy2 = (y4-y3)/numLines;
    for(var i = 0; i <= numLines; i ++){
            line(x1, y1, x4, y4);

            x1 += dx1;
            y1 += dy1;
            x2 += dx2;
            y2 += dy2;
            x3 += dx3;
            y3 += dy3;
    }
}

//light lines
function strt(a1, b1, a2, b2, a3, b3, a4, b4, numLines, colour){
    stroke(colour);
    dx3 = (a4-a3)/numLines;
    dy3 = (b4-b3)/numLines;
    dx1 = (a2-a1)/numLines;
    dy1 = (b2-b1)/numLines;
    dx2 = (a4-a3)/numLines;
    dy2 = (b4-b3)/numLines;
    for(var i = 0; i <= numLines; i ++){
            line(a1, b1, a4, b4);
            a1 += dx1;
            b1 += dy1;
    }

}

//straight lines
function lne(x1, y1, x2, y2, x3, y3, x4, y4, numLines, colour){
    stroke(colour);
    dy1 = (y2-y1)/numLines;
    dy3 = (y4-y3)/numLines;
    for(var i = 0; i <= numLines; i ++){
            line(x1, y1, x3, y3);

            y1 += dy1;
            y3 += dy2;
    }
}