Errata: An erratum was published for this puzzle at 12:30 PM EST 1/14/2018. In the grid at the very bottom of this puzzle, the indicators pointing from the drawings to locations on the grid appeared at different locations depending on what browser you were using and what zoom level your browser was set to. This issue has been corrected; the grid, drawings, and indicators are now displayed as a single image that renders correctly across browsers at any zoom level.