The mod decorates assembling machines, furnaces, mining drill, pump jacks, and chemical plants with an indicator light, making it easier to identify bottlenecks in your factory:

Green: currently doing stuff

Yellow: not currently doing anything, limited by the output

Red: not currently doing anything, limited by the input

The above colors are configurable through the settings menu, e.g., swap out yellow for blue for high contrast.

Hotkey to toggle lights: SHIFT + ALT + L

The mod configuration menu (Game menu -> mods) has the following options:

* Number of machines updated per game tick (Default is 40, i.e. 40 machines/tick * 60 ticks/second=2400 machines/second). This ensures that the mod uses the same amount of time per tick on a small factory as on a large one, but as the factory gets larger, the lights update less frequently. If your factory has 10000 machines, each light will only update roughly once every 4 seconds. Increasing the machines/tick value will improve this at the cost of CPU power.