 			data = @_impl
 			data.from = @_from
 			data.to = @_to
-			pending.push @
+			unless data.pending
+				pending.push @
+				data.pending = true
 
 			data.startTime = nowTime
 			updateAnimation @

				pending[i] = pending[n-1]
				pending[n-1] = pending[pending.length-1]
				pending.pop()
				n--

		requestAnimationFrame vsync


	DATA =
		type: 'number'
		pending: false
		startTime: 0
		pauseTime: 0
		from: 0
