proof it's a backpack: you can see a ">" symbol at the bottom left of the screen, and, right above this symbol, is an upright triangle. if the triangle was part of the design, it would've been very irregular, so it's not part of the design and is actually a visible part of the floor. it also has the same pattern and color as the floor. this indicates that there is a hole between the ">" part and the rest of the bag. the hole isn't at the top of the bag (that's obviously its bottom), therefore the ">" part is a backpack handle, so the bag is a backpack