I've been working on some more background pieces for my Visual Board Game. I thought I'd make a rib cage looking piece.
First of all I made a flat square In the top view. I choose to make it a box and not a planar because I wanted some height to the base. Then i extrude the pillars and with edge select lengthened one side to make a slope.
I had to then move some vertex's up so the arching part wouldn't be as thick:
After this I simply selected the now smaller polygons, extruded them and then raised them to make it diagonal: