Intersection Questions

Each row resolves to 'row 0 AND row 1'. Elements that appear in only one parent disappear; elements common to both carry through. The row-2 cell is necessarily sparser than the parent cells, often dramatically so.

• Row-2 cells contain only elements visible in BOTH row-0 and row-1 parents of the same column.
• Elements present in only one parent never appear in row 2.
• Row 2 is often noticeably sparser than either parent.

• Two overlapping element sets that share a small core.
• A row-2 cell that 'feels minimal' — only the shared elements remain.
• Empty or near-empty results when the parents have little overlap.

1. 1List the elements present in row 0 and row 1 cells of the column you're solving.
2. 2Keep only the elements present in BOTH lists.
3. 3The result is the row-2 cell.
4. 4Verify by checking that any element in row 2 is also in both parents.

• Confusing intersection with XOR — XOR keeps elements present in exactly one parent; intersection keeps elements present in both.
• Treating sparseness as subtraction — subtraction is one-directional; intersection is symmetric.
• Missing elements when both parents have many — the intersection is often just two or three elements.