### Python Program: BMI Calculator

#### Objective:
Write a program that calculates the Body Mass Index (BMI) based on user input of weight in kilograms and height in meters. The program should then categorize the BMI result into standard health categories.

#### Step-by-Step Instructions to Write the Program:

1. **Print an Introduction Message**
- Instruction: Print "Welcome to the BMI Calculator!" to introduce the user to the program.

2. **Prompt for Weight Input**
- Instruction: Ask the user to enter their weight in kilograms with the prompt "Enter your weight in kilograms: " and convert this input to a float.

3. **Prompt for Height Input**
- Instruction: Ask the user to enter their height in meters with the prompt "Enter your height in meters: " and convert this input to a float.

4. **Calculate BMI**
- Instruction: Calculate the BMI using the formula `BMI = weight / (height x height)`. Store the result in a variable.

5. **Classify BMI Result**
- Instruction: Use a series of `if`, `elif`, and `else` statements to classify the BMI value into categories:
- Below 18.5: Underweight
- 18.5 to 24.9: Normal weight
- 25 to 29.9: Overweight
- 30 or above: Obesity

6. **Print the BMI and Category**
- Instruction: Print the calculated BMI and its corresponding category using a formatted string.

7. **Ask User If They Want to Continue**
- Instruction: After showing the BMI and category, ask the user if they want to calculate another BMI. Store the response in a variable.

8. **Decide Whether to Continue or Exit**
- Instruction: Use an `if` statement to check the user's decision. If they do not want to continue, print a goodbye message and end the program.

9. **Loop the Program Based on User Choice**
- Instruction: Use a `while` loop to allow the user to continue calculating BMIs until they choose to stop.