Missing explanation

[PPrasai]

In the first "Introduction" chapter, there is this piece of code to ascertain the next step of the Walker:

void step() {
    float stepx = random(-1, 1);
    float stepy = random(-1, 1);

    x += stepx;
    y += stepy;
}

For some reason, the next step is always drawn relatively to the top-left of current location and the Walker heads in the general direction towards the top-left of the window. Some explanation about why the Walker's behaving like that would be very much appreciated!

[shiffman]

Addressed in noc-book-2 now.