Babies start to sit by they get six months old. It is the best time to introduce the bright colors. The best choice is the stacking cups and rings.
Stacking cups contain the pictures of animals like, elephant, lion, tiger, rabbit and cat. Six cups are enough, and it should be in red, green, blue and yellow colors. I had given my kid the stacking cups of these colors, for one week he did not give any attention. I myself showed him the stacking and nesting. After stacking the cups I allowed him to throw and drop it. On each time I told the names of the animals on it and the colors. After a few days, he started to nest it, as he was not able to stack it properly. He could stack only two or three and slowly he learned the technique. Happily, I saw, his hands and eye co-ordination.
Stacking rings are also helpful, it is more handy, and both rings and cups are safe for kids. They can bite and throw it. It is really exciting as the kids learn how it is arranged by placing the big one in the bottom and the small one on the top. The color will attract his/ her attention. They will love it.