Let n≥2. Let C(n) denote the minimal volume ∣⋃j=1n⋃k=1nPj,k∣ of prisms Pj,k with vertices
(xj,k,yj,k,0),(xj,k+n1,yj,k,0),(xj,k,yj,k+n1,0),(xj,k+n1,yj,k+n1,0), (xj,k+nj,yj,k+nk,1),(xj,k+nj+1,yj,k+nk,1),(xj,k+nj,yj,k+nk+1,0),(xj,k+nj+1,yj,k+nk+1,1)
for some real numbers xj,k,yj,k. Establish upper and lower bounds for C(n) that are as strong as possible.