You can use repeated letters in a columnar transposition key. The important part is deciding which repeated letter comes first. CipherSteps reads tied columns from left to right in their original positions, so both sender and solver can follow the same order.
Put the BALLOON columns in order
| Original position | Key letter | Read order |
|---|---|---|
| 1 | B | 2 |
| 2 | A | 1 |
| 3 | L | 3 |
| 4 | L | 4 |
| 5 | O | 6 |
| 6 | O | 7 |
| 7 | N | 5 |
Read columns 2, 1, 3, 4, 7, 5, 6. The first L stays before the second L, and the first O stays before the second O. Swapping either pair would change the ciphertext, so keep this tie rule with your puzzle instructions.
Repeated letters and a short final row
MEETATNOONKey BALLOON; stable tie order; no paddingEOMOENTNATFind column lengths before sorting
MEETATNOON has ten letters and BALLOON has seven. After one full row, three letters remain. That makes original columns 1, 2, and 3 two letters long, while columns 4–7 hold one letter each. Keep these lengths attached to the original columns when you sort them.
| Read position | Original column | Length | Ciphertext slice |
|---|---|---|---|
| 1 | 2 | 2 | EO |
| 2 | 1 | 2 | MO |
| 3 | 3 | 2 | EN |
| 4 | 4 | 1 | T |
| 5 | 7 | 1 | N |
| 6 | 5 | 1 | A |
| 7 | 6 | 1 | T |
Put the columns back
Place each slice back into its original column, reading down from the top. Then read across the rows to recover MEETATNOON. The extra letters belong to the first three columns in the original grid, not the first three columns after sorting.
Try a smaller tied key
Use key BABA and message ABCDE. Which columns are read first, and which column is longest?