RAINBOW-CUP - This design concept came from colorful rainbow. Apply colorful rings as basic components along with marked volume of each component on its out side. Adding rings equals adding volume of the cup and also equals adding colors to the cup, which not only helps people with drinking volume measurement, but also easily differentiates users' cups by different connecting sequence of color rings, which gets rid of messing up during bigger parties when people use similar cups, evens help with small families. Furthermore, diverse color connecting way promotes people's innovations and shows personalities. The basic components are easy to assemble and disassemble and mating-slot provides waterproof function. Each unit has simple geometric layout and basic material that can be easily manufactured, so, it's definitely affordable and enjoyable.