param_array = [];
ratio = Math.sqrt(2);

function setup() {
	// put setup code here
	createCanvas(512,512)
		param_array.push({
			startx: width/4,
			starty: height/2,
			endx: width/2,
			endy: height/2,
		});
}

function draw() {
	// put drawing code here
	if (param_array.length > 0){
		param = param_array.pop();
			line(param.startx, param.starty, param.endx, param.endy);
			xlen = (param.endx - param.startx)/ratio;
			ylen = (param.endy - param.starty)/ratio;
			if ( Math.max( Math.abs(xlen), Math.abs(ylen)) > 1 ){
				param_array.splice(0,0,{
					startx: param.endx,
					starty: param.endy,
					endx: param.endx-ylen,
					endy: param.endy+xlen,
				});
				param_array.splice(0,0,{
					startx: param.endx,
					starty: param.endy,
					endx: param.endx+ylen,
					endy: param.endy-xlen,
				});
			}
	}
	else noLoop();
}