There's a tentacular horror coming out of the floor!
Actually, no: we have electricians in pulling out the old mainframe power cables and replacing them with standard plugs.
They're on long flexible whips run below the raised floor.
Our "under floor" isn't particularly deep, and it's very crowded in the area that the servers are located.
Turning 180° you can see a cable tray with CAT5 cables (the yellow and blue) and fiber (orange). This is a view I've never really seen before -- the under floor right side up! Usually I'm on my belly sticking my head down under the floor with a flashlight so I see everything upside down.
Today the crew started installing overhead cable tray. The long-term goal is to get all of our data cabling out of the floor and up overhead (where it is much easier to maintain), leaving the underfloor for the cold air and power cables.
The curved piece is a "waterfall" -- to give cables a graceful (pinch-free) path down from the cable tray into the server cabinets.