structure2.js

//openjscad.org
// Anna and Charlie's spral

function main () {
	const twist = 45;
	let i = 0;
	let delta = 1;
	var w = [ ];
    for(var h = 0; h < 100; h++) {
        w.push(
            color('burlywood', cube({
                size: [30, 6, 2],
                center: [15, 3, 1]
            }).translate([0, -18 - i * 2, 1 + h*2])
            .rotateZ(h * twist))
        );

        w.push(
            color('burlywood', cube({
                size: [30, 6, 2],
                center: [15, 3, 1]
            }).translate([0, 18 + i * 2, 1 + h*2])
            .rotateZ(h * twist))
        );

        w.push(
            color('burlywood', cube({
                size:[30, 6, 2],
                center: [15, 3, 1]
            })
            .rotateZ(90)
            .translate([-18 - i *2, 0, 1 + h*2])
            .rotateZ(h * twist))
        );

        w.push(
            color('burlywood', cube({
                size: [30, 6, 2],
                center: [15, 3, 1]
            })
            .rotateZ(90)
            .translate([18 + i *2, 0, 1 + h*2])
            .rotateZ(h * twist))
        );
        
        i = i + delta;
        
        if(h > 0 && h % 8 === 0) {
            delta = -delta;
        }
    }
    return w;
}