i have examples:
i have to find them i just rebuild my computer again...
damn hacker!
or i'll just use daj's
Pattern #3: two seperated functions diffrent digits.
not a dual. paired yes i usually list it under remote pairs.
this is a dual

pattern 1) {it shares mutiple same points}
@ are the linked nodes.
normal elimination due to same links.
- Code: Select all
|-----------+-----------+-----------|
| . . . | . . . | 3 . 3 |
| . . 3 | . . . | . . . |
| . . . | . 3 . | . . . |
|-----------+-----------+-----------|
| . . . | . . . | . 3 . |
| . 3@ . | 3@ . . | . . . |
| 3 . . | . . 3# | . . . |
|-----------+-----------+-----------|
| 3 . . | 3# . . | . . 3 |
| 3 . . | . . . | 3 . 3 |
| 3 3@ . | . . 3# | 3 . . |
+-----------------------------------+
eliminations are
R7C123
R9C456
&
R6C123
R5C456
this is also 1 with 1 shared cell.
overlapping sections dual coverage in boxes
{neting possible extra eliminations.}
Pattern #2
- Code: Select all
+-----------------------------------+
| . . 1 | . . . | . N 1@ |
| . . . | . 1 . | . . . |
| 1# . . | . . . | . 1@ . |
|-----------+-----------+-----------|
| . . . | . . . | 1 . . |
| . . . | . . 1 | . . . |
| . 1 . | . . . | . . . |
|-----------+-----------+-----------|
| . . . | 1 . . | . . . |
| 1@ . N | . . . | . N 1@ |
| . . 1@ | . . . | . 1@ . |
+-----------------------------------+
# is the linked nodes for this example:
elminations are:
R1C123
R3C789
and
R123C3
R789C1
i also belive that the N cells are removed from double coverage since they are linked.
have to check on that one though...
how to define them as duals is an open question...
Some do, some teach, the rest look it up.