def METHOD_NAME(self, start, end, visible):
    spring = helix()
    spring.pos = start.pos
    spring.axis = end.pos-start.pos
    spring.visible = visible
    spring.thickness = 0.05
    spring.radius = 0.5*atom_radius
    spring.length = spacing
    spring.start = start
    spring.end = end
    spring.color = color.orange
    self.springs.append(spring)