I am making a Aztec Pyramid and am most likely going to be stacking square cakes to get the shape, easy enough (I hope!)  However, I am stumped on how I should do the middle "slide" or whatever it is called, lol.   Any suggestions?  Also, for the "stone" I was planning on coloring the fondant light gray and then sponging on darker gray to give it that mottled look.  What do you guys think?  Thanks for any help, I really apprecaite it!

I think  you have to give more details.  The size of the cake matters a lot.

How big will the finished cake be?

The cake will probalby start at 4 inches and go all the way down to 18 inches.  Its the sides I am confused how to make though?  Just wondering how to build out the slope in the middle of the squares?
 

I would probably use rice krispie treats to achieve the 'slides' in the middle- so I would cut a long rectangle for the 'slide', then cut out smaller rectangles to put underneath the 'slide' so it can be flushed with the steps on the cake...does that make sense? I can see it in my head, but its kind of hard to explain it lol. I would probably attach those smaller 'support' rectangles underneath the long slide piece with white chocolate then lay that one whole piece on the cake to replicate the slide.

I didn't even think of using rice crispies!  Thanks for the suggestion.
 

no problem

AOr cut channels out of the middle of each side so you don't have to cut all those rectangles out. I think rkt is a great idea!