A system of m nonzero vectors in ℤn is called an m-icube if they are pairwise orthogonal and have the same length. The paper describes m-icubes in ℤ4 for 2 ≦ m ≦ 4 using Hurwitz integral quaternions, counts the number of them with given edge length, and proves that unlimited extension is possible in ℤ4.