u = 1.5cm;

beginfig(1)

pickup pencircle scaled 0.75pt;

draw (0u, 0u)--(0u, 2u);
draw (1u, 0u)--(1u, 2u);
draw (2u, 0u)--(2u, 2u);
draw (3u, 0u)--(3u, 2u);

draw (0u, 0u)--(3u, 0u);
draw (0u, 1u)--(3u, 1u);
draw (0u, 2u)--(3u, 2u);

fill fullcircle scaled 0.15cm shifted (0u, 0u);
fill fullcircle scaled 0.15cm shifted (0u, 1u);
fill fullcircle scaled 0.15cm shifted (0u, 2u);

fill fullcircle scaled 0.15cm shifted (1u, 0u);
fill fullcircle scaled 0.15cm shifted (1u, 1u);
fill fullcircle scaled 0.15cm shifted (1u, 2u);

fill fullcircle scaled 0.15cm shifted (2u, 0u);
fill fullcircle scaled 0.15cm shifted (2u, 1u);
fill fullcircle scaled 0.15cm shifted (2u, 2u);

fill fullcircle scaled 0.15cm shifted (3u, 0u);
fill fullcircle scaled 0.15cm shifted (3u, 1u);
fill fullcircle scaled 0.15cm shifted (3u, 2u);

fill fullcircle scaled 0.45cm shifted (0.5u, 2u) withcolor white;
fill fullcircle scaled 0.45cm shifted (1.5u, 2u) withcolor white;
fill fullcircle scaled 0.45cm shifted (2.5u, 2u) withcolor white;

fill fullcircle scaled 0.45cm shifted (0u, 1.5u) withcolor white;
fill fullcircle scaled 0.45cm shifted (1u, 1.5u) withcolor white;
fill fullcircle scaled 0.45cm shifted (2u, 1.5u) withcolor white;
fill fullcircle scaled 0.45cm shifted (3u, 1.5u) withcolor white;
                                               
fill fullcircle scaled 0.45cm shifted (0.5u, 1u) withcolor white;
fill fullcircle scaled 0.45cm shifted (1.5u, 1u) withcolor white;
fill fullcircle scaled 0.45cm shifted (2.5u, 1u) withcolor white;

fill fullcircle scaled 0.45cm shifted (0u, 0.5u) withcolor white;
fill fullcircle scaled 0.45cm shifted (1u, 0.5u) withcolor white;
fill fullcircle scaled 0.45cm shifted (2u, 0.5u) withcolor white;
fill fullcircle scaled 0.45cm shifted (3u, 0.5u) withcolor white;
                                               
fill fullcircle scaled 0.45cm shifted (0.5u, 0u) withcolor white;
fill fullcircle scaled 0.45cm shifted (1.5u, 0u) withcolor white;
fill fullcircle scaled 0.45cm shifted (2.5u, 0u) withcolor white;

draw fullcircle scaled 0.45cm shifted (0.5u, 2u);
draw fullcircle scaled 0.45cm shifted (1.5u, 2u);
draw fullcircle scaled 0.45cm shifted (2.5u, 2u);

draw fullcircle scaled 0.45cm shifted (0u, 1.5u);
draw fullcircle scaled 0.45cm shifted (1u, 1.5u);
draw fullcircle scaled 0.45cm shifted (2u, 1.5u);
draw fullcircle scaled 0.45cm shifted (3u, 1.5u);
                                               
draw fullcircle scaled 0.45cm shifted (0.5u, 1u);
draw fullcircle scaled 0.45cm shifted (1.5u, 1u);
draw fullcircle scaled 0.45cm shifted (2.5u, 1u);

draw fullcircle scaled 0.45cm shifted (0u, 0.5u);
draw fullcircle scaled 0.45cm shifted (1u, 0.5u);
draw fullcircle scaled 0.45cm shifted (2u, 0.5u);
draw fullcircle scaled 0.45cm shifted (3u, 0.5u);
                                               
draw fullcircle scaled 0.45cm shifted (0.5u, 0u);
draw fullcircle scaled 0.45cm shifted (1.5u, 0u);
draw fullcircle scaled 0.45cm shifted (2.5u, 0u);

label(btex 1 etex, (0.5u, 2u));
label(btex 2 etex, (1.5u, 2u));
label(btex 3 etex, (2.5u, 2u));

label(btex 4 etex, (0u, 1.5u));
label(btex 5 etex, (1u, 1.5u));
label(btex 6 etex, (2u, 1.5u));
label(btex 7 etex, (3u, 1.5u));

label(btex 8 etex, (0.5u, 1u));
label(btex 9 etex, (1.5u, 1u));
label(btex 10 etex, (2.5u, 1u));

label(btex 11 etex, (0u, 0.5u));
label(btex 12 etex, (1u, 0.5u));
label(btex 13 etex, (2u, 0.5u));
label(btex 14 etex, (3u, 0.5u));

label(btex 15 etex, (0.5u, 0u));
label(btex 16 etex, (1.5u, 0u));
label(btex 17 etex, (2.5u, 0u));

endfig;


end