         middleTree.physicsBody = SKPhysicsBody(rectangleOf: middleTree.size)
         middleTree.physicsBody?.categoryBitMask = PhysicsCategory.Environment
         middleTree.physicsBody?.contactTestBitMask = PhysicsCategory.LeftBomb | PhysicsCategory.RightBomb
+        middleTree.physicsBody?.collisionBitMask = PhysicsCategory.None
+        middleTree.physicsBody?.affectedByGravity = false
         addChild(middleTree)
         
         leftTree.position = CGPoint(x: -147.94, y: -62.205)

        rightTree.physicsBody = SKPhysicsBody(rectangleOf: rightTree.size)
        rightTree.physicsBody?.categoryBitMask = PhysicsCategory.Environment
        rightTree.physicsBody?.contactTestBitMask = PhysicsCategory.LeftBomb | PhysicsCategory.RightBomb
        addChild(rightTree)
    }
    

import MultipeerConnectivity

struct PhysicsCategory {
    static let None             : UInt32 = 0
    static let All              : UInt32 = UInt32.max
    static let RightSquirrel    : UInt32 = 0x1 << 0
    static let LeftSquirrel     : UInt32 = 0x1 << 1
    static let LeftBomb         : UInt32 = 0x1 << 2
