3 different heights, shapes produce a different color for the tea. Here, the tea is Oriental Beauty. A deeper cup makes the tea look darker.
Another interesting observation is that ivory white adds a touch of yellow/gold color to the tea. This is a plus for darker teas (roasted Oolongs, red and black teas). But for green teas or light Oolongs, I would rather recommend celadon or qingbai cups to enhance the green color of the brew.