### Ball?

Generate a 3D sphere-like form using just arc&rectangle drawing.

```// You can find the Turtle API reference here: https://turtletoy.net/syntax
Canvas.setpenopacity(-0.5);

// constant variables
const square_size = 20;

const canvas_size = 256;
const offset_x = 7;
const offset_y = 8;
// Global code will be evaluated once.
const turtle = new Turtle();

function line(x1,y1,x2,y2){turtle.penup();turtle.goto(x1,y1);turtle.pendown();turtle.goto(x2,y2);}
function InCircle(x,y,cx,cy,radius){let dx = x - cx;let dy = y - cy;return dx*dx + dy*dy <= radius*radius;}

function Halton(index, base){let result = 0;let invBase = 1.0 / base;let frac = invBase;while(index>0){result += (index%base)*frac;index /= base;frac *= invBase;}return result;}
function Halton2D(index,base1,base2,range){let HaltonX = Halton(index,base1)-0.5;let HaltonY = Halton(index,base2)-0.5;let x = HaltonX * range;let y = HaltonY * range;return [x,y];}

// The walk function will be called until it returns false.
function walk(i) {
let A = Halton2D(i,2,3,canvas_size);
let x = A[0], y = A[1];
let inCircle = false;

{
{
let scale = k / radius_levels.length;
for(let m = 0;m<k;m++)
{
}

inCircle = true;
}
}

if(!inCircle)
{
square(x+offset_x,y+offset_y,square_size);
}

return i < 10000;
}
```