The Storage unit can store one shape up to 5,000 units. This can be used as buffer for product or for temporary storage when a shape isn't needed to free up space around the hub. A useful property of the Storage is that it can be used as an overflow gate. If the Storage unit is empty, it will pass all inputs to the left output. However, if it contains items, or if the left output is blocked, it will begin outputting to the right. This property is used in some freeplay factories to automatically pass shapes through a Stacker or Painter if only one input is present.
The Storage unit also has two wire outputs: one on the left side that checks whether the unit is at maximum capacity, and one that outputs the shape currently stored in the unit. You can also double throughput by connecting two lanes carrying the same shape to the inputs and a regular balancer and two lanes to the outputs.
Storage in the wires layer