fid = fopen('mtest.mask', 'rb');
dat = fread(fid, inf, 'uchar');
fclose(fid);

dat = reshape(dat, [8 8 8]);
pcolor(dat(:, :, 1)');

r = 3;
s = 0:pi / 20:2 * pi;
c0 = [4.9, 4.1];
x = c0(1) + r * cos(s);
y = c0(2) + r * sin(s);

hold on;
plot(x, y, 'y-');
