text: //
  //  PHYAttachmentBehavior.h
  //  PHYKit
  //
  //  Created by Nora Trapp on 8/3/13.
  //  Copyright (c) 2013 Nora Trapp and Zev Eisenberg. All rights reserved.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  #import "PHYDynamicBehavior.h"
  
  typedef NS_ENUM(NSInteger, PHYAttachmentBehaviorType)
  {
      PHYAttachmentBehaviorTypeItems,
      PHYAttachmentBehaviorTypeAnchor
  };
  
  @interface PHYAttachmentBehavior : PHYDynamicBehavior
  
  - (instancetype)initWithItem:(id <PHYDynamicItem>)item attachedToAnchor:(CGPoint)point;
  - (instancetype)initWithItem:(id <PHYDynamicItem>)item offsetFromCenter:(PHYOffset)offset attachedToAnchor:(CGPoint)point;
  
  - (instancetype)initWithItem:(id <PHYDynamicItem>)item1 attachedToItem:(id <PHYDynamicItem>)item2;
  - (instancetype)initWithItem:(id <PHYDynamicItem>)item1 offsetFromCenter:(PHYOffset)offset1 attachedToItem:(id <PHYDynamicItem>)item2 offsetFromCenter:(PHYOffset)offset2;
  
  @property (readonly, nonatomic) PHYAttachmentBehaviorType attachedBehaviorType;
  
  @property (readwrite, nonatomic) CGPoint anchorPoint;
  
  @property (readwrite, nonatomic) CGFloat length;
  @property (readwrite, nonatomic) CGFloat damping; // 1: critical damping
  @property (readwrite, nonatomic) CGFloat frequency; // in Hertz
  
  @end
  