let field;

​

function setup() {

  createCanvas(600, 400);

  let widthPx = height - 2 * marginPx;

  let lengthPx = width - 2 * marginPx;

  field = new Field(marginPx, marginPx, lengthPx, widthPx);

  background(222);

  field.draw();

}

​

​

​