The tiles in this game is composed to illustrate the world from the view of a cat. The designer had gave most attention to the major tiles that represent big objects. This might be because that cats have a bad eyesight, so they can only pay attention to the big items in the room, like the table and chairs in the living room or desks and beds in the bedroom. Objects that are given even more attention to are the objects that have a close relationship to the cat in the game, like the water bowl, the fridge, food, or its own bed. Although they should be items, most of those tiles are made as sprites for them to be able to trigger the dialogues for multiple times in the game. Sometimes the designer will use multiple tiles to build one image, like the big table in the living room, or the big bed in the bedroom. The tiles that caught less attention is the tiles that construct the rooms. They're just simple walls and stairs that cat won't pay much attention to.
The grass tile is particular in this game, it's also the only animated tile in the game. The animation gives an impression of wind blowing over the lawn outside of the house. This is the part where the designer fighting with bitsy, when a room full of single grass tile can produce an impression more than that. As a cat that loves to be out door, the lawn seems much bigger than the crowded inner part of the house, like it could stretch for ever.