Our network at Curious had some partial outages recently (one portion of the network was down but others weren't). I set these up to monitor each portion of the network's ability to connect to the internet. Some are connected to switches, others are connected to WAPs. They each hit a different deadmanssnitch.com url so I can see their status remotely and get notified.
The blink1s are at less than 25% brightness (#005500) to keep heat down and are still plenty bright.
Having a single physical object for each monitored network might seem like overkill at first glance, but for network monitoring this could be ideal: each RasPi is a self-contained full computer with network connection on the net segment in question. The RasPi could perform all sorts of diagnostic tests on a specific Ethernet segment without tricky switch/router configuration changes. A great solution, John!