Back in 2012, Steven Spielberg was set to direct an adaptation of Daniel H. Wilson’s Robopocalypse. But a year later, Spielberg delayed the project and put it back in development, with no dedicated timeframe for getting the film made. If you were wondering what it might have (or might still) look like, new concept art shows us some of the character and tech designs intended for the film.

The concept art popped up on via artist Patrick Janicke, and highlights robotic designs of a couple of different varieties. There’s the grungy, beat-up older versions, and newer, sleeker models. There’s also a robotic neck accessory, various weapons, and a surgical bot, as well as a little cast-off battle-bot with a face reminiscent of WALL-E.

Without context, it’s difficult to figure out how these designs were intended to be implemented in the final product. Spielberg previously developed a screenplay for Robopocalypse with Drew Goddard, but in 2013 the director said that he found a new, more personal way to tell the story and was planning on taking “half a year” to get it right. It’s 2015 now, and we still have no update on Robopocalypse.

Here’s the official synopsis for Wilson’s novel:

In this terrifying tale of humanity’s desperate stand against a robot uprising, Daniel H. Wilson has written the most entertaining sci-fi thriller in years. Not far into our future, the dazzling technology that runs our world turns against us. Controlled by a childlike—yet massively powerful—artificial intelligence known as Archos, the global network of machines on which our world has grown dependent suddenly becomes an implacable, deadly foe. At Zero Hour—the moment the robots attack—the human race is almost annihilated, but as its scattered remnants regroup, humanity for the first time unites in a determined effort to fight back. This is the oral history of that conflict, told by an international cast of survivors who experienced this long and bloody confrontation with the machines. Brilliantly conceived and amazingly detailed, Robopocalypse is an action-packed epic with chilling implications about the real technology that surrounds us.

Spielberg is in post-production on Bridge of Spies and The BFG, and it’s not currently clear what his next move might be. He’s developing a Michael Crichton novel for DreamWorks, though he’s likely only acting as producer on that project.