Unusual Cube Chair ID  

Architect-designed one-off or custom commission ?

Looks like a cut-down church pew.

Heh-heh -- from a pretty loungey, laid-back church ?
Is that rotary fir plywood ?

Yeah, this seems like some sort of build. SDR, went back and took some more photos. I'm not a woodsmith and not sure sure which part you're referring to. I do think the bottom seat is a plywood.  As for the rest of the piece I wouldn't know but will upload some more shots for the discussion.

Thanks.  The panels are surely plywood, an appropriate material for that circumstance. I assume the chair is missing its seat and back cushions, simple upholstered rectangles.  The wear mark on the inside of the side panel shows where the sitter was located, I suppose.

Yeah, it is without the cushions. Wish that weren't the case. So you believe the side panels and the arms are plywood? I never would have thought that. So my walnut assumptions were way off?
The underneath seems so unfinished compared to the outside of the piece.
Here are some more detail shots and closups of the hardware used.
 

mrwright, if you google images of "fir plywood", you'll see the same grain pattern as on the side and back panels of your chair.  It has been stained so the color isn't that of fir, but the grain sure is.  
The seat base is very homemade-looking.  I have stripped down a lot of chairs and can't think when I've seen a webbed base that was plywood.  Maybe on a Pearsall chair or two but most of those are framed, even---I think.  (This is not a Pearsall that I've ever seen.)
 

Those square drive screws are not that old. 

A cut-out panel of plywood is a decent, even smart, base panel, to accept webbing -- assuming the broad perimeter doesn't limit the area of resilience.  No corner joints to worry about !
Most common production furniture has a lower degree of finish on unseen faces, like the bottom.
One sure way to eliminate solid wood is to compare both faces of a panel.  With veneer the two faces won't show the same grain pattern on both sides . . . and the joints between pieces won't align, as they must with solid planks.

Leif, credit where credit is due.
Robertson screws have been common in Canada for a looong while. It's only since the wide use of cordless power screwdrivers that their superior (to Phillips) design for this application has popularized them here in the US and elsewhere.
 
http://en.wikipedia.org/wiki/List_of_screw_drives#Robertson

As usual tktoo, you are more correct that I am.  
However, unless the chair in Canada (or rather near the border), then I think the point stands that those screws would not be very old.

Thanks for info on wood you guys.  I'm still learning about the finer details of materials. The design of the chair is what first caught my attention and thus my inquiry.
And as far as screws go, I'm in Washington and very close to the Canadian border. So there's that...

Well, then, the proximity to Canada means the screw heads don't mean much of anything.