In the problem description a valid solution should also work for a 1-column matrix with more than one 1 row, like [4; 2]: "If the input has one column, the output should be identical to the input."
But solution 170924 submitted on 30 Nov 2012 (Size: 23, the leading solution) does not work in this case.
I wonder why such a case is not evaluated by the test suite.