Wag Worms

When intergalactic Wag Worms are born they look just like a cube.

Each year they grow another cube in any direction (except on their faces of course). So a Wag Worm in its second year might look like any of these.

The next year it grows another cube onto its second cube (not its face cube). So one shape a Worm in its third year can be is this:

Find all the shapes that a Wag Worm in its third year can be.