I propose this puzzle interesting to you in my opinion for the multiple possibilities to solve it.
.4.95..7......61.3..7....5....5....129.....683....4....6....7..4.83......5..12.8.
Hidden Text: Show
Sincerely
Robert
.------------------------.-----------------.-------------------------.
| a16[8] 4 b[2]16 | 9 5 3 | b[28]6 7 c6#2 |
| 5 a[82] h(9)-2 | 2478 2478 6 | 1 g249 3 |
| 689 3 7 | 1248 248 18 | 24689 5 2469 |
:------------------------+-----------------+-------------------------:
| 678 78 46 | 5 2689 89 | 2349 2349 1 |
| 2 9 45 | 17 3 17 | 45 6 8 |
| 3 18 156 | 268 2689 4 | 259 f29 7 |
:------------------------+-----------------+-------------------------:
| 19 6 e(2)139 | 48 489 589 | 7 f12349 d459#2 |
| 4 127 8 | 3 679 579 | 269 129 2569 |
| 79 5 39 | 467 1 2 | 3469 8 469 |
'------------------------'-----------------'-------------------------'
.-----------------.--------------------.---------------------.
| 168 4 h12 | 9 5 3 | 268 7 26 |
| 5 i(2)8 9 | c2478 c2478 6 | 1 d[4]-2 3 |
| 68 3 7 | 1248 be24#8 f18 | 24689 5 2469 |
:-----------------+--------------------+---------------------:
| 78 78 46 | 5 b26 9 | 3 a[2]4 1 |
| 2 9 45 | 17 3 17 | 45 6 8 |
| 3 1 56 | 268 268 4 | 25 9 7 |
:-----------------+--------------------+---------------------:
| 19 6 g12 | 48 489 f58 | 7 3 g2459 |
| 4 27 8 | 3 679 57 | 269 1 2569 |
| 79 5 3 | 467 1 2 | 469 8 469 |
'-----------------'--------------------'---------------------'
+---------------------+----------------------+-------------------------+
| 168 4 126 | 9 5 3 | 268 7 26 |
| 5 28 29 | 2478 2478 6 | 1 249 3 |
| 689 3 7 | 1248 248 18 | 24689 5 2469 |
+---------------------+----------------------+-------------------------+
| 678 78 46 | 5 2689 89 | 2349 2349 1 |
| 2 9 45 | 17 3 17 | 45 6 8 |
| 3 18 156 | 268 2689 4 | 259 29 7 |
+---------------------+----------------------+-------------------------+
| 19 6 1239 | 48 489 589 | 7 12349 2459 |
| 4 127 8 | 3 679 579 | 269 129 2569 |
| 79 5 39 | 467 1 2 | 3469 8 469 |
+---------------------+----------------------+-------------------------+
(2)r2c4 - (29=4)r2c38@
||
(2-1)r3c4 = r3c6 - (1=7)r5c6 - (7)r8c6
|| ||
(5)r8c6 - - - - - - - r7c6 = = = = = = = (5)r7c9 - - - - - - - -
|| || \
(9)r8c6 - (9=8)r4c6 - r4c1 = r13c1 - (8=2)r2c2 - r8c2 = (2)r7c3 - (2)r7c9
|| ||
(2)r7c3 - r8c2 = r2c2 - (29=4)r2c38@
|| ||
(2)r7c8 - (29=4)r26c8@
||
(2)r6c4 - (6)r6c4 = (6-4)r9c4 = r7c45 - (4)r7c8
\ ||
(2)r4c5 = = = (23)r4c78 - - - (4)r4c8
||
(4)r2c8@
-----------------------------------------------
=> +4 r2c8; ste