?? action of gl(n.Z) on ... ????"points" of group alg of Z^n ?? ... ???... ??? .....

?? n=1 and projective line ?? ...

?? n=2 and ... ???...

??? Z^2 as not very "cube-ish" (or even square-ish ...) ... in terms of its automorphisms ... ??? .....

??? attaching "fringes" to torus ... ??? ....