I resolved my problem by doing this :

Code:

for(int i = 0; i < MAX_SZ; i++)
{
x = 49;
for(int j = 0; j < MAX_SZ; j++)
{
if(map[i][j] == 1)
{
//putpixel(x, y, BLUE);
line(x, y, x + 15, y);
line(x + 15, y, x + 15, y + 15);
line(x + 15, y + 15, x, y + 15);
line(x, y, x, y + 15);
}
x += 15;
}
y += 15;
}

The idea is probably that your grid may well be 21x21, but each "cell" is more than one pixel large. However large your pacman is -- that's how large everything should be. So if it's a wall, you don't just draw a pixel worth of blue; you make it a box of blue.

That & an expresso really drove the point home