Implement a method to draw a circle. You are not allowed to use math library functions such as `sqrt`

, `sin`

, or `cos`

.

For example, given r = 2 (radius), return the following points to plot:

```
(0,0), (0,1),(0,2), (1,0), (1,1), (2,0), (0,-1), (0,-2), (-1,0), (-1,1), (1,-1), (-1,-1),(-2,0)
```

Note that all points satisfy the equation: `x^2 + y^2 <= r^2`

.