32 lines, no comments · 223 tokens, written in 2 seconds for $0.0006

 1  let x, y;
 2  
 3  function setup() {
 4    createCanvas(400, 400);
 5    background(220);
 6    x = width / 2;
 7    y = height / 2;
 8  }
 9  
10  function draw() {
11    stroke(0);
12    point(x, y);
13  
14    let choice = floor(random(4));
15    switch (choice) {
16      case 0:
17        x++;
18        break;
19      case 1:
20        x--;
21        break;
22      case 2:
23        y++;
24        break;
25      case 3:
26        y--;
27        break;
28    }
29  
30    x = constrain(x, 0, width - 1);
31    y = constrain(y, 0, height - 1);
32  }