I'm just throwing this out ther, my wife got this picture frame about five or six years ago [it could even be more] and I've never put the pictures in that she wanted. To say she's miffed about it is an understatment so I finally stripped off the packaging and started to sort it out but as soon as i put it down on the table I just saw the perfect piece of terrain to base an Underhive or City Fight table on. There's definitely scope to put all sorts of creating and mesh layers as walkways. Fill some of the openings with industrial waste or rubble then build up some of the other frames with GW building walls. Now the chance of getting this again is practically non-existent, but I'm sure there are similar examples. This was about £13 from Dunelm Mill [or the Range] it's geat because you have three layers thanks to the stacked plastic framework. It's also two identical rectangula pieces joined together to make the square, so there's additional scope to look for something similar that may be rectangular.
Sadly I'll not be able to create the vision that popped into my head as soon as I placed it flat on the table, but I had to share the concept in case anyone else would similarly inspired. I just found the whole epiphany of an item that has been loitering in my house for ages suddenly took on a whole new perspective.