Each finder pattern is wrapped on its inner edges by a one-module light border so it cannot blur into the data beside it. Today you draw those separators.
Place the one-module light separator along the inner edges of each finder.
Right next to each finder pattern the symbol places a separator: a one-module-wide line of light modules along the finder’s inner edges - the edges that face the rest of the grid. Without it, a dark data module touching the finder’s dark border could smear the 1:1:3:1:1 ratio the scanner keys on, so the separator guarantees a clean light boundary around each finder.
For the top-left finder that means the whole of row 7 (columns 0 through 7) and the whole of column 7 (rows 0 through 7) are light, forming an L that hugs the finder. The top-right and bottom-left finders get the same treatment on the edges that face inward. These modules are light function patterns: fixed, and off-limits to data. With the finders fenced off, the two thin dotted lines that calibrate module spacing come next.
// Top-left finder: light row just below (row 7, cols 0..7)// and light column just right (col 7, rows 0..7).for i := 0; i <= 7; i++ {g.set(7, i, 0)g.set(i, 7, 0)}// Mirror for the other two finders on their data-facing edges.