I tried placing some objects in space without drawing the perspective grid. Do these look like they are all on the same plane?

Just starting out on this website. I've been slowly studying the basics for awhile now (not very good at them) & finally checked out proko, subsequently bought a few courses that looked interesting. I figure posting any assignments I do to my profile will be helpful to me & maybe anyone else looking at this so here is the first one. I am morphing primitive shapes from chapter 1 in Introduction to Drawing, by Ryan Benjamin.