This truck is parked where another person was shot.
The May 4 memorial, called ‘the 7 percent solution’ because only 7 percent of the planned design was actually built. The school held a contest to design a memorial, but the first winner turned out to be a Canadian. So they went with the design of the runner up, but only partially completed it.
I do not know the official story on why the memorial was never completed, although I think I can understand if the other 93% also looked like what was actually built.