Squidport tiles
I think it's just one of those things that you have to keep plugging at, even when you think you don't necessarily need a tile.
Forum Discussion
Stackables disappeared at the same time as the ability to clean up a neighbor's graffiti or tap on the Simpson home three times in three minutes. No structure can be tapped more than once until the town's owner logs on. Although some buildings can be tapped again as soon as their town is synced, with graffiti they definitely need to clean it and with squidport they definitely need to build a new tile. Thus, no stacking. It also makes inactive neighbors way more obvious, since now they'll literally have nothing to tap on. All kind of a bummer, really.
