Hi Camilo,
Maybe this is too late, but anyway,
n=3;
initConf = ReplacePart[Table[0, {2 n + 1}, {2 n + 1}], Random[Integer, {1, 4}], {n + 1, n + 1}]
I played around with your Meander function. It was quite educational.
If you take the Table part:
n=3;
Table[0, {2 n + 1}, {2 n + 1}]//MatrixForm
And execute it, you'll get this:
The table size is {2 n + 1},{2 n + 1}, which is an odd number. The center of the table is at { n + 1},{n + 1} and the ReplacePart is putting a random number right in the center.
ReplacePart[Table[0, {2 n + 1}, {2 n + 1}], Random[Integer, {1, 4}], {n + 1, n + 1}]//MatrixForm
Eric