Took about 20 minutes to write some python code to search; takes about 1/3 of a second to try all 3x17x17 mutations and find at least one rectangle produced by

Took about 20 minutes to write some python code to search; takes about 1/3 of a second to try all 3x17x17 mutations and find at least one rectangle produced by each. So yeah, every single-point change "destroys" the solution.