Answer: 0-1 months: A black and white high-contrast soft toy. The black and white contrasts will help to stimulate the baby's vision.
1-2 months: A soft plush toy that rattles or makes crinkling sounds. The sounds will help to develop the baby's auditory skills.
3-4 months: A soft plush toy with different textures. The baby will start to reach out and touch objects, so this toy will help to develop their sense of touch.
5-6 months: A stacking toy. The baby will start to grab and hold objects, and this toy will help to develop their hand-eye coordination and fine motor skills.
7-8 months: A toy that makes music. The baby will start to show an interest in music, and this toy will help to develop their auditory skills.
9-10 months: A toy that has light and sound. The baby will be more curious about their surroundings and this toy will help to develop their sense of cause and effect.
11-12 months: A pull toy. The baby will start to take their first steps, and this toy will help to develop their balance and coordination.
The colors and sizes of the toys can vary, but they should be appropriate for the baby's age and size. They should also be made of safe materials that are free of harmful chemicals.