code: func Rect(x0, y0, z0, x1, y1, z1 float32) Rectangle {
  	if x0 > x1 {
  		x0, x1 = x1, x0
  	}
  	if y0 > y1 {
  		y0, y1 = y1, y0
  	}
  	if z0 > z1 {
  		z0, z1 = z1, z0
  	}
  	return Rectangle{Vec3{x0, y0, z0}, Vec3{x1, y1, z1}}
  }
docs: // Rect is shorthand for Rectangle{Vec3(x0, y0), Vec3(x1, y1)}. The returned
  // rectangle has minimum and maximum coordinates swapped if necessary so that
  // it is well-formed.