Test all four grid boundaries

The problem

Grid movement can wrap from one row to another if only index arithmetic is checked.

Practical procedure

Assert that moving left from column zero and right from column six never changes position.

Worked scenario

From cell index 6, right must be blocked instead of moving to the next row's first cell.

Acceptance check

Automate edge checks for top, bottom, left and right on all boundary cells.

Apply the method

Use the related interactive tool to try the concept on an inspectable example. Record the starting assumptions and expected result before changing settings, then compare what the tool actually does. Where the result differs, keep the release marked experimental and document the discrepancy.

Further reading: Relevant primary technical documentation. This guide is an educational procedure, not a substitute for independent usability or compliance review.